External Features Of The Frog Quiz

The posterior opening of the digestive tract is referred to as the anus. It is the opening through which waste materials are eliminated from the body. The other options listed, such as the eardrum, snout, and iris, are not related to the digestive tract or waste elimination.

The pigmented structure surrounding the pupil is called the iris. The iris is responsible for controlling the size of the pupil and determining the amount of light that enters the eye. It contains muscles that contract or expand to adjust the size of the pupil, allowing more or less light to enter the eye. The iris also gives the eye its color, as the pigmentation of the iris varies from person to person. Therefore, the correct answer is A. Iris.

The flattened, triangular, blunt apex of the head is commonly referred to as the snout. The snout is a prominent feature in many animals, especially those that rely heavily on their sense of smell. It is typically elongated and contains the nostrils, which are used for breathing and detecting scents. The snout can vary in shape and size depending on the species, but it is generally a distinguishing characteristic of animals such as pigs, dogs, and elephants.

The question asks for the structure that is protruding on the dorso-lateral sides of the head. The cornea is a part of the eye, so it cannot be the correct answer. The pupil is a part of the eye, so it cannot be the correct answer. Therefore, the correct answer is Eyes, as they are the structures that protrude on the dorso-lateral sides of the head.

The anterior opening of the digestive tract refers to the opening through which food enters the body. In most animals, including humans, this opening is called the mouth. The mouth is responsible for the intake of food and the initial process of digestion, such as chewing and breaking down food into smaller pieces. Therefore, it is the correct answer in this context.

The correct answer is "Nictitating membrane." The nictitating membrane is a transparent membrane that is located above the lower eyelid in certain animals, such as birds, reptiles, and some mammals. This membrane acts as a protective covering for the eye, helping to keep it moist and shield it from debris and other potential hazards. It can also be used to protect the eye while still allowing some vision, as it is transparent.

The dark central oval opening seen through the cornea is known as the pupil. The pupil is responsible for controlling the amount of light that enters the eye by dilating or constricting. It appears dark because it contains no pigmentation and allows light to pass through to the retina. It is not the mouth or the nictitating membrane, which are unrelated structures.

The cornea is the clear, transparent part of the eye that covers the iris, pupil, and anterior chamber. It acts as a protective layer and helps to focus light onto the retina, allowing us to see clearly. The cornea is responsible for about two-thirds of the eye's total focusing power. It is essential for maintaining the shape and integrity of the eye, and any damage or disease to the cornea can significantly affect vision.

The eardrum, also known as the tympanic membrane, is a circular membrane located posterior to the eye. It is a thin, delicate structure that separates the outer ear from the middle ear. When sound waves enter the ear canal, they cause the eardrum to vibrate, which then transmits the vibrations to the middle ear bones, allowing for the process of hearing. Therefore, the correct answer is Eardrum.

The correct answer is Nostril. The question is asking about pairs of openings that are located postero-dorsal to the snout. The only option that fits this description is the nostril, as it is located on either side of the snout and is responsible for the sense of smell. The iris is the colored part of the eye and is not located near the snout. The eardrum is located in the middle ear, not near the snout. The mouth is not an opening, but rather a cavity.