The animal's digestive tract forms from the _______.

The ectoderm is on the outside of the developing embryo.

The innermost layer of the blastocyst is the

The middle layer of the blastocyst is the

Long supporting rod that runs through a chordate's body just below the nerve chord.

One of a pair of structures in the throat region of a chordate.

Process in which a stimulus produces a response that opposes the original stimulus; also called negative feedback.

Body plan in which any number of imaginary planes drawn through the center of the body could divide into equal halves.

Body plan in which a single imaginary line can divide the body into left and right sides that are mirror images of each other.

The innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system.

Body cavity lined with mesoderm

Body cavity that is only partially lined with mesoderm.

Hollow ball of cells that develops when a zygote undergoes a series of cell divisions.

An animal whose mouth is formed from the blastopore

Group of animals in which the blastopore becomes an anus, and the mouth is formed from the second opening that develops

Concentration of sense organs and nerve cells at the anterior end of an animal.