Most arachnids have ____ pair(s) of jointed appendages.

Bone cells communicate with one another by:

In a negative feedback system, ____.

Oil immersion

The epidermis of a nematode is derived from the:

What type of product comes from the breakdown of lactose?

Both smooth muscle fibers and cardiac muscle fibers:

Within the chordate classes, the unique characteristic of the class Aves is:

What term describes how most sponges can produce both male and female gametes?

A ____ plane divides the animal body into dorsal and ventral parts.