Module 13

Question 1

Invertebrates

Answer 1

Animals that lack a backbone

Question 2

Vertebrates

Answer 2

Animals that possess a backbone

Question 3

Spherical symmetry

Answer 3

An organism possesses spherical symmetry if it can be cut into two identical halves by any cut that runs through the organism’s center

Question 4

Radial symmetry

Answer 4

An organism possesses radial symmetry if it can be cut into two identical halves by any longitudinal cut through its center

Question 5

Bilateral symmetry

Answer 5

An organism possesses bilateral symmetry if it can only be cut into two identical halves by a single longitudinal cut along its center that divides it into right and left halves

Question 6

Anterior end

Answer 6

The end of an animal that contains its head

Question 7

Posterior end

Answer 7

The end of an animal that contains its tail

Question 8

Epidermis

Answer 8

An outer layer of cells designed to provide protection

Question 9

Endodermis

Answer 9

An inner layer of cells

Question 10

Mesenchyme

Answer 10

The jellylike substance that separates the epidermis from the inner cells in a sponge

Question 11

Collar cells

Answer 11

Flagellated cells that push water through a sponge

Question 12

Amoebocytes

Answer 12

Cells that move using pseudopods and perform different functions in different animals

Question 13

Gemmule

Answer 13

A cluster of cells encased in a hard, spicule-reinforced shell

Question 14

Polyp

Answer 14

The sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other

Question 15

Medusa

Answer 15

A free-swimming cnidarian with a bell-shaped body and tentacles

Question 16

Epithelium

Answer 16

Animal tissue consisting of one or more layers of cells that have only one free surface, because the other surface adheres to a membrane or other substance

Question 17

Mesoglea

Answer 17

The jellylike substance that separates the epithelial cells in a cnidarian

Question 18

Nematocysts

Answer 18

Small capsules that contain a toxin that is injected into prey or predators

Question 19

Testes

Answer 19

Organs that produce sperm

Question 20

Ovaries

Answer 20

Organs that produce eggs

Question 21

Closed circulatory system

Answer 21

A system in which blood stays in vessels designed to transport food and other necessary substances throughout a creature’s body

Question 22

Nervous system

Answer 22

A system of sensitive cells that respond to stimuli such as sound, touch, and taste

Question 23

Ganglia

Answer 23

Masses of nerve cell bodies

Question 24

Hermaphroditic

Answer 24

Possessing both the male and the female reproductive organs

Question 25

Regeneration

Answer 25

The ability to regrow a missing part of the body

Question 26

Open circulatory system

Answer 26

A system in which blood is pumped through vessels into various chambers or body cavities where it comes in direct contact with cells, tissues, and organs

Question 27

Mantle

Answer 27

A sheath of tissue that encloses the vital organs of a mollusk, makes the mollusk's shell, and functions in respiration, waste disposal, and sensory perception

Question 28

Visceral hump

Answer 28

A hump that contains a mollusk's heart, digestive, and excretory organs

Question 29

Foot

Answer 29

A muscular organ that is used for locomotion and takes a variety of forms depending on the animal

Question 30

Radula

Answer 30

An organ covered with teeth that mollusks use to scrape food into their mouths

Question 31

Univalve

Answer 31

An organism with a single shell

Question 32

Bivalve

Answer 32

An organism with two shells