Question 1

The function of the chorion is to:

Accepted Answer

The chorion is a membrane that lines the inside of the eggshell in reptiles, birds, and monotremes (egg-laying mammals). Its primary function is to allow gas exchange, providing oxygen to the developing embryo and removing carbon dioxide.

Question 2

Monozygotic twins:

Accepted Answer

Monozygotic twins are also called identical twins because they come from a single fertilized egg that splits into two embryos. They have the same set of genes and are usually the same sex.

Question 3

Which of the following are incorrectly paired?

Accepted Answer

The answer of Which of the following are incorrectly paired?
...

Question 4

Compare and contrast the roles of cell division and morphogenesis in the development of an animal.

Accepted Answer

The answer of Compare and contrast the roles of cell...

Question 5

Figure 51-3  Refer to the accompanying figure. The chorion is identified by number:

Accepted Answer

The answer of Figure 51-3  Refer to the accompanying...

Question 6

Figure 51-3  Refer to the accompanying figure. The amnion is identified by number:

Accepted Answer

The answer of Figure 51-3  Refer to the accompanying...

Question 7

In humans, the allantois:

Accepted Answer

The answer of In humans, the allantois:
...

Question 8

In mammals, the ____ is a temporary center for the formation of blood cells.

Accepted Answer

The yolk sac is a membranous sac attached to the embryo that is a temporary source of nutrition for the developing embryo. In mammals, the yolk sac also serves as a site of early blood cell formation, until the liver and spleen take over this function later in development. The other structures listed (amnion, allantois, chorion, archenteron) do not have a role in blood cell formation.

Question 9

The embryo becomes implanted in the endometrium of the uterus due to:

Accepted Answer

The answer of The embryo becomes implanted in the endometrium...

Question 10

The percentage of twins being born has increased in the past 20 years because of:

Accepted Answer

The increased use of fertility inducing drugs such as clomiphene and gonadotrophins has led to a higher rate of twin births in the past 20 years. These drugs stimulate ovulation and increase the likelihood of multiple eggs being released, which can result in twins or even higher-order multiple births.

Question 11

The first breath of the neonate is initiated by the:

Accepted Answer

The first breath of a neonate is primarily initiated by the accumulation of carbon dioxide in the blood. This build-up of CO2 leads to a decrease in blood pH, stimulating the respiratory center in the brain to initiate breathing.

Question 12

Which structure is the most immediate precursor of the brain?

Accepted Answer

The neural tube is the most immediate precursor of the brain, as it forms from the neural plate and eventually develops into the central nervous system, including the brain and spinal cord.

Question 13

A teratogen is a drug that:

Accepted Answer

A teratogen is a drug, chemical, or virus that can interfere with the normal development of a fetus and cause birth defects. It does not increase fertility, prevent fertilization or induce labor. However, it can prevent implantation of the embryo in the endometrium or interfere with morphogenesis, which is the process of normal embryonic development. Therefore, the best choice is E, interfering with morphogenesis.

Question 14

The trophoblast secretes ____, which signals the corpus luteum that pregnancy has begun.

Accepted Answer

The trophoblast secretes hCG (human chorionic gonadotropin), which signals the corpus luteum that pregnancy has begun. This hormone prevents the degeneration of the corpus luteum and stimulates it to continue producing progesterone and estrogen to maintain the endometrium and support the developing embryo.

Question 15

Relate nuclear equivalence and differential gene expression.

Accepted Answer

The answer of Relate nuclear equivalence and differential gene expression....

Question 16

Place the following in developmental order beginning with the earliest event.
1) limb buds appear
2) face begins to look human
3) muscles differentiate
4) downy hair covers the fetus
5) sex can be determined by external inspection

Accepted Answer

The answer of Place the following in developmental order beginning...

Question 17

A human embryo is capable of movement and has gonads that are distinguishable as either testes or ovaries by the end of the:

Accepted Answer

The answer of A human embryo is capable of movement...

Question 18

Which statement about early embryonic development in humans is FALSE?

Accepted Answer

The embryo actually enters the uterus several days after fertilization, not 24 hours after. Typically, this process takes about 3-4 days, not 1 day as stated in option C.

Question 19

Figure 51-3  Refer to the accompanying figure. The allantois is identified by number:

Accepted Answer

The answer of Figure 51-3  Refer to the accompanying...

Question 20

The extraembryonic membrane closest to the embryo is the:

Accepted Answer

The amnion is the extraembryonic membrane that surrounds the developing embryo and is closest to it. It is filled with amniotic fluid, which provides a protective cushion for the developing embryo. The other options (B-D) are also extraembryonic membranes, but they are not the closest membrane to the embryo. The neural plate (E) is not an extraembryonic membrane at all, it is a structure that develops into the central nervous system.

Quiz 51: Animal Development

The function of the chorion is to:

Monozygotic twins:

Which of the following are incorrectly paired?

Compare and contrast the roles of cell division and morphogenesis in the development of an animal.

Figure 51-3 Refer to the accompanying figure. The chorion is identified by number:

Figure 51-3 Refer to the accompanying figure. The amnion is identified by number:

In humans, the allantois:

In mammals, the ____ is a temporary center for the formation of blood cells.

The embryo becomes implanted in the endometrium of the uterus due to:

The percentage of twins being born has increased in the past 20 years because of:

The first breath of the neonate is initiated by the:

Which structure is the most immediate precursor of the brain?

A teratogen is a drug that:

The trophoblast secretes ____, which signals the corpus luteum that pregnancy has begun.

Relate nuclear equivalence and differential gene expression.

Place the following in developmental order beginning with the earliest event. 1) limb buds appear 2) face begins to look human 3) muscles differentiate 4) downy hair covers the fetus 5) sex can be determined by external inspection

A human embryo is capable of movement and has gonads that are distinguishable as either testes or ovaries by the end of the:

Which statement about early embryonic development in humans is FALSE?

Figure 51-3 Refer to the accompanying figure. The allantois is identified by number:

The extraembryonic membrane closest to the embryo is the: