Animal Structure and Function Chapter 12

An earthworm has a(n) exoskeleton.

• True

• False

Nerve nets a have a central ring?

• true

• false

Hydrostatic skeletons are different from other skeletons in that they are soft.

• true

• false

Animals with radial symmetry have brains or brain-like structures.

• true

• false

Octopuses use jet propulsion to move.

• true

• false

Sponges exchange gases through spiracles.

• true

• false

Muscles surround blood vessels in open circulatory systems.

• true

• false

What is a hydrostatic skeleton?

• It is a fluid-filled internal cavity surrounded by muscle tissue.

• It is a hard outer covering, such as a shell.

• It is a hard internal structure made out of bone.

• It is a hard internal structure made out of cartilage.

All skeletal systems provide support to organisms, but only two types are hard. Which lists the two hard skeletons?

• exoskeletons and hydrostatic skeletons

• exoskeletons and endoskeletons

• endoskeletons and hydrostatic skeletons

• exoskeletons and shells

The fluid filled cavity of a hydrostatic skeleton is called which of the following?

• vertebrate

• invertebrate

• backbone

• coelom