Exam 29: Reproduction and Development

Animal species in which the offspring tend to move away from their parents to live in slightly different habitats are likely to benefit from

Morphogens act in humans as well as in other animals, such as fruit flies.

Which of the following does not affect development in animals?

In mammals, the blastocyst consists of the trophoblast and the

The mitochondria in your cells are a mix of the mitochondria found in your father's sperm and your mother's egg cell because the contents of the sperm cytoplasm are dumped into the egg cell during fertilization.

Examine this close-up of the placenta (on the left of the figure). Why do the chorionic villi have the shape of a tree?

Animal sperm cells tend to be larger than animal egg cells.

In humans, the yolk sac

Genes are generally switched on or off by the presence proteins called __________.

One reason that fertilization rarely occurs between the gametes of two different species might be that the plasma membranes of the gametes of different species do not contain the same __________ so the membranes of the sperm and the egg cannot fuse.

Which of the following would not be exchanged between a mother and her fetus through the umbilical cord?

Embryonic stem cells have the greatest potential for creating medical treatments because they

The body retains stems cells after embryonic development is complete because

In the last few weeks of pregnancy, the level of estrogen in a woman's blood rises. This causes

Which one of the following methods of reproduction is not used by animals?

During development, the process by which unspecialized cells acquire specific identities is called

The three layers of cells in a human embryo are ectoderm, endoderm, and ________.

The skulls of newborn humans and chimpanzees closely resemble each other.

Some organisms switch from male to female, or vice versa. The most likely rationale for the change is the

By the end of a normal first trimester, the zygote