Sperm and egg fuse to produce a cell called a _______. Once this cell starts dividing, it is referred to as a(n) _______.

In animal development, the process of cleavage produces a ball of cells with an interior cavity. In the succeeding evelopmental process, called gastrulation, the cells in the embryo migrate to form three layers of cells, the _______, _______, and _______, which in terms of location are the _______, _______, and ________ layers of cells in the organism.

In vertebrates, a support structure called a notochord serves to _______, or bring about, the development of a structure called the neural tube, which gives rise to both the _______ and _______.

In what way is development a good example of a biological process that is self-regulating?

In what order do the following developmental steps occur?

a. organogenesis

b. fertilization

c. blastula formation

d. morula formation

e. gastrulation

The process of gastrulation involves;

a. massive cell death.

b. little or no growth of the embryo.

c. development of three tissue layers.

d. organogenesis.

e. cell enlargement.

Organogenesis is accomplished, in part, by the ability of some cells to bring about developmental change in other cells. This process is referred to as:

a. reduction.

b. transformation.

c. translation.

d. induction.

e. fusion.

The cells that migrate from the developing neural tube and eventually form different organs and tissues throughout the body are:

a. neural crest cells.

b. archenteron cells.

c. mesenchyme cells.

d. stem cells.

e. endoderm cells.

Morphogens (select all that apply):

a. diffuse from one group of cells to another.

b. are cell adhesion molecules.

c. work through concentration gradients.

d. bring about production of transcription factors.

e. are active only in nervous system development.

The homeobox DNA sequence is said to be ____ because _____.

a. an induction sequence; it controls general development

b. highly unusual; it exists in only a few animals

c. a diversifying influence; it brings about differences in animals

d. fast-evolving; it changes every few generations

e. highly conserved; it has changed little over evolutionary time

The segregation of cells into different layers in development is strongly shaped by ______, while the transformation of the human hand from its webbed to its five-fingered form is strongly shaped by

a. morphogens; neural crest cells

b. cell adhesion; apoptosis

c. homeobox sequences; morphogens

d. apoptosis; cell adhesion

e. induction; neural crest cells