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A rise in the quality of prenatal care.
Increased exposure to new sources of radiation.
C) better physical condition of potential mothers.
Increased use of fertility drugs.
Better nutrition available for potential mothers.
It allows animals that do not move around to produce offspring without finding mates.
Offspring without finding mates. B) It allows an animal to produce many offspring quickly
It produces genetically uniform populations
It allows a population to expand quickly to exploit available resources.
It saves the time and energy required to produce gametes.
Sexual reproduction allows animals to expand their populations faster than asexual reproduction
Populations of organisms that reproduce through sexual reproduction generally have difficulty adapting to changing environments.
Sexual reproduction produces 2n gametes.
Sexual reproduction generates greater genetic variation than asexual reproduction.
Sexual reproduction creates an individual that is a genetic copy of one parent.
Must fertilize themselves
Have abnormal reproductive systems
Possess both male and female reproductive systems.
Develop from unfertilized eggs.
Have the gonads of one sex but the external appearance of the other.
Animals that are widely dispersed
Populations with many more females than males.
Populations with many more males than females
The corpus luteum secretes progesterone, which helps maintain the uterine lining during pregnancy
The labia minora are a pair of thick, fatty ridges that protect the entire genital region.
The cervix is an important structure of sexual arousal
In human females, eggs develop within the uterus.
After 9 months of development, an embryo is called a fetus.
Rhythmic contractions of the uterus
Rhythmic contractions of the oviduct
The beating of the eggʹs flagella
The beating of the eggʹs cilia
The beating of cilia in the oviduct
Upper third of the oviduct.
Lower third of the oviduct.
So the testes can be kept away from the urinary bladder
To shorten the distance that semen must travel during ejaculation
To shorten the distance that sperm must swim during insemination
So the testes can enlarge during sexual maturation
So the testes can be kept cooler than the bodyʹs interior
Produce healthier sperm
Produce more sperm
Produce fewer sperm
Produce more sperm and ones that are healthier.
Produce nonfunctional sperm.
Spermatogenesis begins at birth
Meiosis in spermatogenesis produces two cells from one primary spermatocyte
Oogenesis is not completed without stimulation by estrogen.
Meiosis in oogenesis produces one mature egg from one primary oocyte
Oogenesis begins at puberty
During oogenesis, there is a resting period that lasts for about 30 days
Spermatogenesis, but not oogenesis, is an example of gametogenesis
Spermatogenesis and oogenesis rely upon mitosis to produce gametes
Men, but not women, can produce gametes throughout their lives.
During oogenesis, four cells are produced with each sharing equally the cytoplasm from the parent cell.
Is triggered by HCG
Is triggered by an increase in the levels of estrogen and progesterone.
Is triggered by an LH surge.
Coincides with the postovulatory phase of the ovarian cycle.
Coincides with the beginning of the pre-ovulatory phase of the ovarian cycle.
The level of progesterone drops precipitously
The levels of estrogen reach their maximum
The hypothalamus increases its release of FSH and LH.
The hypothalamus stimulates the anterior pituitary to increase its output of FSH and LH.
The levels of FSH and LH drop precipitously
Using birth control pills
Using a diaphragm and spermicide
Abstaining from sexual intercourse
Using condoms and spermicides
The rhythm method.
Natural family planning is generally reliable.
Morning-after pills taken within three days of unprotected intercourse prevent fertilization or implantation about 75% of the time.
Birth control pills work primarily by preventing fertilization and implantation.
Spermicides used alone are generally reliable.
The most widely used birth control pills contain a combination of FSH and LH
Mitochondria in the sperm tail
The sperm plasma membrane
Mitochondria in the sperm head
Mitochondria in the neck and middle piece
Activates development in the egg.
Joins two diploid sets of chromosomes and activates development in the egg
Joins two diploid sets of chromosomes
Joins two haploid sets of chromosomes
Joins two haploid sets of chromosomes and activates development in the egg.
Formation of more cells
Formation of the nervous system
Formation of the digestive system
Formation of the notochord
Slicing up a pie into eight pieces
Inflating a balloon
Stringing beads onto a string
Stretching a rubber band
Melting a stick of butter in a hot pan
Establish the basic tissues of the body and define the future digestive tract
Create a multicellular embryo and establish the basic tissues of the body.
Create a multicellular embryo and partition the embryo into developmental regions
Establish the basic tissues of the body and define the future nervous system
Establish the basic body plan and determine the location of the mouth and anus.
Embryonic nervous system.
Space between the ectoderm and endoderm
Outer layer of the gastrula
Embryonic digestive tract.
A solid embryo is changed into a hollow morula.
A hollow blastula is changed into a hollow embryo that has three tissue layers
A notochord is created by invagination of the ectoderm.
A solid blastula is changed into a hollow embryo that has four tissue layers
A neural tube is created by invagination of the ectoderm