STS - Student Testing Service

The error is in option B. The word "has" should be changed to "have" to match the plural subject "People".

When a skeletal muscle cell contracts, the sarcomere, which is the basic unit of muscle contraction, reduces in length. The H-zone, which is the region in the center of the sarcomere where only thick filaments are present, also reduces in size. Additionally, the I-band, which is the region in the sarcomere where only thin filaments are present, also reduces in size. Therefore, all of these changes occur when a skeletal muscle cell contracts.

Diagram B represents a cell undergoing metaphase 1 of meiosis because it shows homologous chromosomes aligning at the center of the cell. During metaphase 1, homologous chromosomes pair up and align at the equatorial plate of the cell. This is depicted in Diagram B where the chromosomes are arranged in pairs along the center of the cell. Diagrams A, C, and D do not show this characteristic alignment of homologous chromosomes, making B the correct answer.

The correct answer is trigonal pyramidal. In NH3 (ammonia), there are three bonding pairs and one lone pair of electrons around the central nitrogen atom. This arrangement leads to a pyramid-like shape, with the three hydrogen atoms positioned at the base and the lone pair at the apex. The bond angles between the hydrogen atoms are slightly less than 109.5 degrees, which is the ideal tetrahedral angle. Therefore, the geometry of NH3 is trigonal pyramidal.

The correct answer is that the sarcoplasmic reticulum regulates the level of Ca2+ within muscle cells. The sarcoplasmic reticulum is a specialized type of endoplasmic reticulum found in muscle cells. It plays a crucial role in muscle contraction by storing and releasing calcium ions. When a muscle is stimulated to contract, the sarcoplasmic reticulum releases calcium ions into the muscle cell, which then bind to the protein troponin, initiating the contraction process. After contraction, the sarcoplasmic reticulum actively pumps calcium ions back into its storage, allowing the muscle to relax.

When an external voltage is applied to a junction in such a direction that it cancels the potential barrier, it is called forward bias. In forward bias, the positive terminal of the battery is connected to the p-type material and the negative terminal is connected to the n-type material. This causes the depletion region to narrow, allowing current to flow easily through the junction. Forward bias is commonly used in electronic devices such as diodes and transistors to allow current to flow in a controlled manner.

Structure 6 is the correct answer because it is the only option that has both exocrine and endocrine function. Exocrine function refers to the secretion of substances through ducts, while endocrine function refers to the secretion of substances directly into the bloodstream.

The Balmer series is a series of spectral lines in the emission spectrum of hydrogen. It corresponds to transitions between energy levels in the hydrogen atom where the electron jumps to or from the second energy level. These transitions result in the emission of visible light. Therefore, the Balmer series contains the visible region of light.

Xerophytes have small thick leaves to limit the water by reducing the surface area. This adaptation helps xerophytes to minimize water loss through transpiration, as the reduced surface area decreases the exposure of the leaves to the surrounding environment. Additionally, the thick leaves also serve as a protective layer, preventing excessive water loss and protecting the plant from harsh environmental conditions such as high temperatures and strong winds. By reducing the surface area, xerophytes are able to conserve water and survive in dry and arid habitats.

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The incorrect statement is "Xylem is situated on the outer side of the cambium ring and the phloem on the inner side." In reality, xylem is located on the inner side of the cambium ring, while the phloem is situated on the outer side.

Peter is from Holland. This is mentioned in the passage where it says, "My friend's name is Peter. Peter is from Amsterdam, in Holland. He is Dutch."

The correct answer is XcY. In normal genetic predication, color blindness is a sex-linked recessive trait carried on the X chromosome. Since the girl is color blind (XcXc), she must have inherited the color blindness allele from her father. The father's genetic makeup must be XcY, as he passed on the X chromosome with the color blindness allele to his daughter.

Rectified spirit is a highly concentrated form of alcohol that is purified through a distillation process. It typically contains a high percentage of alcohol, often around 85%. This makes it suitable for various industrial and medical uses, as well as for making alcoholic beverages. The other options provided, such as 4%, 11%, 90%, and 99.99%, are not as accurate because they do not reflect the high concentration typically found in rectified spirit.

The work done due to centripetal force for circular motion is zero because the centripetal force always acts perpendicular to the displacement of the object. In other words, the force and displacement are at right angles to each other, resulting in zero work being done. This is because work is defined as the product of force and displacement in the direction of the force, and since there is no displacement in the direction of the force, the work done is zero.

The correct answer is Thylakoid membrane. The light reaction of photosynthesis occurs in the thylakoid membrane, which is located within the chloroplasts of plant cells. This is where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH. These energy-rich molecules are then used in the subsequent dark reaction (Calvin cycle) to produce glucose and other organic compounds. The stroma is the fluid-filled space surrounding the thylakoid membrane, while the mitochondria and nucleus are not directly involved in the light reaction of photosynthesis.

The word "an" should be replaced with "a" before the word "useful" because the word "useful" starts with a consonant sound.

The given reaction, H2+I2->2HI, does not depend on pressure. Pressure is the force exerted by a gas on its surroundings and does not affect the formation of the products in this reaction. The reaction can proceed at any pressure, as long as the reactants are present. The rate of the reaction may be affected by pressure, but the overall outcome of the reaction remains the same.

In an isochoric process, the volume remains constant. Since there is no change in volume, there is no work done by or on the system. Therefore, any change in internal energy can only be attributed to a change in heat. This is because the only way for the internal energy to change is through the transfer of heat energy.

The myelin sheath is a protective covering that surrounds axons, allowing for faster and more efficient transmission of electrical impulses. However, the myelin sheath is not continuous along the entire length of the axon. Instead, it is interrupted at regular intervals by small gaps called nodes of Ranvier. These nodes play a crucial role in the conduction of nerve impulses. They allow the electrical signal to "jump" from one node to the next, speeding up the transmission of the signal along the axon.

The molecular orbital picture of O2 indicates two unpaired electrons. In molecular orbital theory, electrons are distributed in molecular orbitals formed by the overlap of atomic orbitals. In the case of O2, the molecular orbital diagram shows that there are two unpaired electrons in the antibonding pi* orbitals. This means that O2 has two unpaired electrons available for bonding, making it a paramagnetic molecule.

An ohm meter is used to measure electrical resistance. It is a device that measures the resistance in ohms of a circuit or component. By connecting the ohm meter to the circuit or component, it can provide an accurate reading of the resistance. This allows for quick and efficient measurement of resistance in various electrical systems.

The end product of translation is a polypeptide. Translation is the process in which the mRNA sequence is decoded by ribosomes to synthesize a chain of amino acids, which then folds into a functional protein. Therefore, the correct answer is polypeptide.

The error in the sentence is in option B. There should not be any extra space between "me" and "a". The correct sentence should be "It takes me a hour to reach the mosque."

Lichens are an example of mutualism because they are a symbiotic relationship between a fungus and an alga or cyanobacterium. The fungus provides a protected environment and absorbs nutrients for both organisms, while the alga or cyanobacterium produces food through photosynthesis. This mutually beneficial relationship allows both organisms to thrive and is an example of mutualism in nature.

The current through R3 can be calculated using Ohm's Law, which states that the current flowing through a resistor is equal to the voltage across the resistor divided by the resistance. In this case, the voltage across R3 is 8V and the resistance is 5 ohms. Therefore, the current through R3 is 8V/5 ohms = 1.6A.

As we move down a group in the periodic table, the size of the atoms increases due to the addition of new energy levels. This increase in size leads to a decrease in the effective nuclear charge experienced by the outermost electrons. As a result, these electrons are less strongly attracted to the nucleus and are easier to remove, leading to a decrease in ionization enthalpies. Therefore, the correct answer is "decrease".

The power of a lens is measured in diopters. Diopters represent the refractive power of a lens and indicate the degree to which the lens can converge or diverge light. It is a unit of measurement that quantifies the lens' ability to bend light rays. The higher the diopter value, the stronger the lens and the more it can bend light. This measurement is commonly used in optometry and ophthalmology to determine the appropriate prescription for corrective lenses.

Hess's Law states that the total enthalpy change of a reaction is independent of the pathway taken. This means that the enthalpy change of a reaction can be calculated by considering the enthalpy changes of the individual steps involved, regardless of the intermediate reactions or the method used to achieve the final reaction. In other words, the enthalpy change is additive and can be determined by summing the enthalpy changes of the individual steps. This property allows for the addition of enthalpies, making Hess's Law a fundamental principle in thermochemistry.

Uranium is not an isotope of hydrogen. Isotopes of hydrogen include deuterium, protium, and tritium. Uranium is a separate element and is not related to hydrogen isotopes.

The correct answer is Glomerulus. The glomerulus is a network of tiny blood vessels located in the renal cortex of the kidney. It is responsible for filtering waste products, excess water, and electrolytes from the blood to form urine. It plays a crucial role in the first step of urine formation in the nephron.

Identical twins are formed when a single fertilized egg, also known as a zygote, splits into two separate embryos. This means that they have the same genetic material and are essentially clones of each other. Therefore, the best description of identical twins is that they are twins from a single egg.

When a man breathes deeply, the diaphragm becomes flattened and the external intercostal muscles contract. This allows the lungs to expand and fill with air. The diaphragm, which is a dome-shaped muscle located at the base of the lungs, flattens out when it contracts, creating more space in the chest cavity for the lungs to expand. The external intercostal muscles, which are located between the ribs, also contract to lift and expand the ribcage, further increasing the lung capacity. This combination of actions allows for a deeper inhalation of air.

Torque depends upon the location of the axis because it is the rotational equivalent of force. It is a measure of the force's ability to cause an object to rotate around an axis. The distance between the axis of rotation and the point where the force is applied determines the torque. The larger the distance, the greater the torque. Therefore, the location of the axis is a crucial factor in determining the torque.

One coulomb is equal to the charge of 6.25x10^18 electrons.

The correct answer is kidney-->ureter-->urinary bladder--->urethra. This is the correct route of urine excretion from the kidney to the outside of the body. The urine is produced in the kidney, then it travels through the ureter, which is a tube that connects the kidney to the urinary bladder. From the urinary bladder, the urine is then expelled out of the body through the urethra.

The change in internal energy of an ideal gas can be calculated using the equation ΔU = Q - W, where ΔU is the change in internal energy, Q is the heat absorbed, and W is the work done by the gas. In this case, the gas is expanding under a constant pressure, so the work done can be calculated as W = PΔV, where P is the pressure and ΔV is the change in volume. Plugging in the given values, we have W = (20 MPa)(0.050 - 0.025) = 0.5 MJ. Since the heat absorbed is 1500 J, the change in internal energy is ΔU = 1500 J - 0.5 MJ = 1000 J. Therefore, the correct answer is 1000 J.

Force and acceleration are related to each other through Newton's second law of motion. According to this law, the force acting on an object is equal to the mass of the object multiplied by its acceleration. In other words, force is directly proportional to acceleration and mass. Therefore, force and acceleration are vector quantities that have a cause-and-effect relationship.

Conjugation is not an electrophilic reaction of benzene. Electrophilic reactions involve the attack of an electrophile on the electron-rich benzene ring. Nitration, halogenation, sulphonation, alkylation, and acylation are all examples of electrophilic reactions where an electrophile reacts with the benzene ring. However, conjugation refers to the delocalization of electrons in a molecule, which can occur in benzene due to its alternating double bonds. It is not a reaction in itself, but rather a property of the molecule.

Destructive distillation is the process used to produce coke from bituminous coal. In this process, coal is heated in the absence of air, causing it to break down into various by-products, including coke. This method is commonly used in the production of coke as it allows for the separation of valuable components such as coal gas, coal tar, and coke.

Night blindness is caused by a deficiency of Vitamin A. Vitamin A is essential for the proper functioning of the retina, which is responsible for vision in low light conditions. A lack of Vitamin A can lead to a condition called night blindness, where individuals have difficulty seeing in dim light or at night. Consuming foods rich in Vitamin A, such as carrots, spinach, and sweet potatoes, can help prevent night blindness and maintain good vision.

Late blight potato disease is caused by the pathogen Phytophthora infestans. This pathogen is a type of water mold, which is a type of fungus-like organism. It infects the leaves, stems, and tubers of potato plants, causing dark, watery lesions that can lead to the destruction of the entire plant. Phytophthora infestans is notorious for its ability to spread rapidly and cause devastating epidemics in potato crops. It is responsible for the Irish Potato Famine in the 1840s, which resulted in the death and displacement of millions of people.

When a ball is dropped freely, it falls under the influence of gravity. The acceleration due to gravity is approximately 9.8 m/s^2. Using the equation d = 1/2 * a * t^2, where d is the distance, a is the acceleration, and t is the time, we can calculate the distance covered by the ball. Plugging in the values, we get d = 1/2 * 9.8 * 4^2 = 78.4 meters. Therefore, the ball of 10kg will cover approximately 78.4 meters in 4 seconds when dropped freely.

The correct answer is Blastula. The blastula stage is the earliest stage of embryonic development in animals, including chicks. During this stage, the fertilized egg undergoes rapid cell division and forms a hollow ball of cells called a blastula. This stage is characterized by the formation of a fluid-filled cavity called the blastocoel. Eventually, the blastula will undergo further development and give rise to the gastrula stage, where the three primary germ layers are formed.

Heartwood is the innermost part of the tree trunk that is no longer active in water transport. It is formed from the transformation of the secondary xylem. The primary xylem refers to the first xylem tissue that develops in the growing parts of the plant, while the secondary xylem is the xylem tissue that forms as the plant grows thicker. Therefore, the correct answer is secondary xylem.

The correct answer is "Hyber process". However, there is no information provided in the question about the different methods of preparing ammonia. Therefore, it is not possible to provide a specific explanation for why the Hyber process is the correct answer.

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The sperms produced by seminiferous tubules are stored in the epididymis. The epididymis is a long, coiled tube located on the back of each testicle. It serves as a storage and maturation site for sperm. Sperms that are produced in the seminiferous tubules pass through the epididymis where they gain the ability to swim and fertilize an egg. When a man ejaculates, the sperm is propelled from the epididymis into the vas deferens, which carries it out of the body.

The oxidation of a secondary alcohol results in the formation of a ketone. This is because secondary alcohols have two alkyl groups attached to the carbon atom bearing the hydroxyl group. During oxidation, the hydrogen atom attached to the carbon atom is removed, and the resulting carbonyl group forms a double bond with the carbon atom. This leads to the formation of a ketone, which contains a carbonyl group bonded to two alkyl or aryl groups.

Heating phenol with Zn will yield benzene. This is because Zn acts as a reducing agent and removes the hydroxyl group (-OH) from phenol, resulting in the formation of benzene.

H2S is the correct answer because it is a covalent hydride. Covalent hydrides are compounds in which hydrogen is bonded to a nonmetallic element through a covalent bond. In H2S, hydrogen is bonded to sulfur through a covalent bond, making it a covalent hydride. The other options, NaBH4, ZnH2, NaH, and CaH2, are not covalent hydrides as they involve hydrogen bonding with metallic elements or ionic bonding.

Lamarck might have explained the auk's loss of the ability to fly with the hypothesis that the auk stopped using its wings, causing them to become smaller. According to Lamarck's theory of inheritance of acquired characteristics, traits acquired during an organism's lifetime can be passed on to future generations. In this case, Lamarck would argue that the auk's offspring inherited the smaller wings because the parent auk stopped using its wings.

The correct answer is 4 because the question asks how many languages the family speaks, and the answer option 4 suggests that the family speaks 4 languages.

The given statement describes Coulomb's Law, which states that the electric force between two static point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. This law quantifies the relationship between electrical charges and the forces they exert on each other, providing a fundamental principle in the field of electrostatics.

The rate-determining step of an SN1 reaction is always the slow step. In an SN1 reaction, the leaving group first dissociates from the substrate, forming a carbocation intermediate. This step is relatively slow because it involves the breaking of a bond. The subsequent step, which involves the nucleophile attacking the carbocation, is fast in comparison. Therefore, the slow step, where the carbocation is formed, determines the overall rate of the reaction.

Fungi store the surplus food in glycogen. Glycogen is a complex carbohydrate that serves as a storage form of glucose in fungi. It is similar to the way animals store excess glucose in the form of glycogen in their liver and muscles. Glycogen can be broken down into glucose when energy is needed by the fungi. This storage mechanism allows fungi to have a readily available source of energy when resources are scarce.

The stable electronic configuration of Cu is [Ar]4s1, 3d10. This means that the Cu atom has a total of 29 electrons. The [Ar] represents the electron configuration of the noble gas argon, which has 18 electrons. The 4s1 indicates that there is one electron in the 4s orbital, and the 3d10 indicates that there are 10 electrons in the 3d orbital. This configuration is stable because it follows the Aufbau principle, which states that electrons fill orbitals in order of increasing energy.

Tarzan is swinging on a vine in a vertical circle, so the force of gravity is acting as the centripetal force. The centripetal acceleration can be calculated using the formula a = v^2 / r, where v is the velocity and r is the radius of the circle. In this case, the velocity is given as 5m/s and the radius can be found by using the length of the vine and the angle it makes with the vertical. By using trigonometry, the radius is found to be 3.84m. Plugging these values into the formula, the centripetal acceleration is calculated to be approximately 6.5m/s^2.

Structure 3 refers to the renal tubules in the kidneys. In this structure, almost all glucose and amino acids are reabsorbed. This means that these important molecules are taken back into the bloodstream from the tubules, preventing their loss in urine. This reabsorption process helps maintain the body's glucose and amino acid levels.

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In non-cyclic photophosphorylation, NADP+ (nicotinamide adenine dinucleotide phosphate) is reduced to NADPH. This process occurs during the light-dependent reactions of photosynthesis, specifically in the photosystem I. NADPH is an important molecule in the Calvin cycle, where it acts as a reducing agent to convert carbon dioxide into glucose. Non-cyclic photophosphorylation involves the transfer of electrons from water to photosystem II, then to photosystem I, and finally to NADP+ to produce NADPH.

Ruby is a crystal of Al2O3, which is also known as aluminum oxide. Ruby is a red gemstone and is a variety of the mineral corundum. Corundum is composed of aluminum and oxygen, with the chemical formula Al2O3. Ruby gets its red color from trace amounts of the element chromium. It is a precious gemstone and is highly valued for its beauty and rarity.

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The correct association is lysosome: digestive enzyme for intracellular use. Lysosomes are organelles that contain digestive enzymes, which break down waste materials and cellular debris within the cell. These enzymes are used to break down macromolecules such as proteins, lipids, and carbohydrates. Lysosomes play a crucial role in cellular digestion and recycling processes.

A terrestrial telescope consists of two convex lenses and one concave lens. The convex lenses are used to gather and focus light, while the concave lens is used to correct the image and make it upright. The two convex lenses work together to magnify the image, and the concave lens helps to correct any distortion. This combination of lenses allows for clear and magnified viewing of terrestrial objects.

CaH2 is the correct answer because it is calcium hydride. Calcium hydride is commonly used in laboratories to generate hydrogen gas. When CaH2 reacts with water, it produces hydrogen gas and calcium hydroxide. This reaction is often used as a convenient method for generating hydrogen gas in the laboratory. Therefore, CaH2 is the most likely hydride to be used for the formation of hydrogen in a laboratory setting.

The depicted structure is involved in homeostasis of extracellular ionic strength. This means that it helps maintain a stable balance of ions outside of cells. This is important for proper functioning of cells and overall bodily functions.

The reverse process of esterification is saponification. Esterification is the process of combining an alcohol and an acid to form an ester, while saponification is the process of breaking down an ester into its original alcohol and acid components. Therefore, saponification is the reverse process of esterification. Filtration, halogenation, and the breakdown of fats are not related to the reverse process of esterification.

The reaction between formaldehyde and ethyl alcohol can result in the formation of a hemiacetal. A hemiacetal is formed when an alcohol group reacts with an aldehyde group, resulting in the formation of a new carbon-oxygen bond. In this case, the formaldehyde acts as the aldehyde group and ethyl alcohol acts as the alcohol group. Therefore, the correct answer is hemiacetal.

All of the given examples are examples of uniform circular motion. The rotation of the Earth around the sun and the spinning of the Earth both involve circular motion, and they both occur at a constant speed. Similarly, the rotation of a flying wheel around its own axis also involves circular motion at a constant speed. Therefore, all of the given options are examples of uniform circular motion.

NH4OH contains ionic, covalent, and coordinate bonds. The NH4+ ion in NH4OH has a covalent bond between nitrogen and hydrogen atoms. The OH- ion has an ionic bond between oxygen and hydrogen atoms. Additionally, the NH4+ ion donates a lone pair of electrons to the OH- ion, forming a coordinate bond. Therefore, NH4OH contains all three types of bonds.

Dispersion of light refers to the phenomenon where light is separated into its constituent colors, known as its components. This occurs when light passes through a medium, such as a prism, and is refracted at different angles depending on its wavelength. As a result, the different colors of light are spread out, creating a spectrum. This process is responsible for the formation of rainbows and the colorful patterns seen when white light passes through a glass prism.

The question is asking to identify a structure part of the circulatory system. The correct answer is 1, but without further information or context, it is impossible to determine what specific structure is being referred to.

The amount of liquid does not have an effect on boiling point because boiling point is determined by the temperature at which the vapor pressure of the liquid equals the atmospheric pressure. The amount of liquid does not affect this equilibrium condition.

The given compound has a propyl group (CH3-CH2-CH2-) attached to the double bond. The propyl group is substituted with an ethyl group (C2H5), hence the name "2-Ethyl prop-1en". The number 2 indicates the position of the ethyl group on the propyl chain, and the "en" ending indicates the presence of a double bond.

When the pressure is increased in the reaction N2 + 3H2 -> 2NH3, the reaction will shift forward. This is because increasing the pressure favors the side with fewer moles of gas. In this reaction, there are 4 moles of gas on the left side (N2 + 3H2) and only 2 moles of gas on the right side (2NH3). Therefore, increasing the pressure will cause the reaction to shift forward to reduce the number of gas molecules and reach a new equilibrium.

The ulna and humerus meet at the elbow joint and allow movement in one plane only.

Arginine is in a different chemical category than the others because it is an amino acid, while the rest are nucleobases. Amino acids are the building blocks of proteins and have different chemical properties and functions compared to nucleobases, which are the building blocks of DNA and RNA.

The correct answer is self inductance. Self inductance is a property of a circuit that causes a change in the current flowing through it to induce an electromotive force (EMF) in the same circuit. It is measured in henries, which is the unit named after Joseph Henry, an American scientist who made significant contributions to the study of electromagnetism. Therefore, the "Henry" is a unit of self inductance.

The Calvin cycle is composed of 13 main reactions. These reactions take place in the stroma of chloroplasts and are responsible for converting carbon dioxide into glucose. During the Calvin cycle, energy from ATP and NADPH, which are produced in the light-dependent reactions, is used to power the synthesis of glucose. The cycle involves a series of enzymatic reactions, including carbon fixation, reduction, and regeneration of the starting molecule, RuBP. Overall, the Calvin cycle plays a crucial role in photosynthesis by capturing and converting carbon dioxide into usable energy in the form of glucose.

The 3p orbital has the lowest energy among the given options. This is because the energy levels of orbitals increase as the principal quantum number (n) increases. In this case, the 3p orbital has a lower principal quantum number (n=3) compared to the 4s, 4f, and 5f orbitals, which have higher values of n. The 3d orbital also has a higher energy level than the 3p orbital, as the d orbitals have higher energy than the p orbitals within the same principal quantum number.

The correct answer is pituitary gland. The pituitary gland is responsible for producing and releasing prolactin hormone, which activates the mammary glands to start producing milk. The pancreas is responsible for producing insulin and regulating blood sugar levels. The thyroid gland produces hormones that regulate metabolism. The thymus gland plays a role in the development of the immune system. The adrenal gland produces hormones such as cortisol and adrenaline.

In a zero-order photochemical reaction, the rate of the reaction is independent of the concentration of the reactants. This means that increasing or decreasing the concentration of the reactants will not affect the rate of the reaction. The rate of the reaction is solely determined by the intensity of the light source. This type of reaction is often observed when the reactants are present in excess and the reaction is limited by the availability of light.

During the contraction of a muscle, myosin binds and releases actin. This is a key step in the sliding filament theory of muscle contraction. When calcium ions are released into the muscle cell, they bind to troponin, causing tropomyosin to move and expose binding sites on the actin filament. Myosin heads then bind to these exposed sites and undergo a power stroke, pulling the actin filament towards the center of the sarcomere. The myosin then releases the actin and prepares for another cycle of binding and releasing, leading to muscle contraction.

The probability that the daughter will be color blind is 0.50. This is because the trait for red green color blindness is sex-linked and recessive, meaning that it is carried on the X chromosome. The man is color blind, so he must have the recessive allele for color blindness on his X chromosome. The woman's father is color blind, so he must have the recessive allele on his X chromosome as well. Since the woman has normal vision, she must have at least one dominant allele for normal vision on her X chromosome. Therefore, the daughter has a 50% chance of inheriting the recessive allele from her father and being color blind.