| A | B |
|---|
| Euglena | a green, single-celled organism with a flagellum, sometimes forming a green scum on stagnant water |
| Ameoba | a single-celled animal that catches food and moves about by extending fingerlike projections of protoplasm |
| Paramecium | a single-celled freshwater animal that has a characteristic slipperlike shape and is covered with cilia |
| Volvox | a green, single-celled aquatic organism that forms minute, free-swimming spherical colonies |
| Eyespot | a small area of light-sensitive pigment in some protozoans, algae, and other simple organisms. Also an eyelike marking found on the wings of certain butterflies. |
| Flagellum | a slender threadlike structure, especially a microscopic whiplike appendage that enables many protozoa, bacteria, spermatozoa, and more, to swim |
| Cilia | tiny hairlike extensions that move together in a sweeping motion |
| Psuedopods | a temporary protrusion of the protoplasm, as of certain protozoans, usually serving as an organ of locomotion or prehension |
| Cell Membrane | a cell structure that controls which substances can enter or leave the cell |
| Cell Wall | a rigid layer of nonliving material that surrounds the cells of plants and some other organisms |
| Nucleus | the control center of a cell that directs the cell's activities and contains the information that determines the cell's form and function |
| Chloroplast | a structure in the cells of plants and some other organisms that captures energy from sunlight and uses it to produce food |
| Mitochondria | rod-shaped cell structures that convert energy in food molecules to energy the cell can use to carry out its functions |
| Vacuoles | a sac inside a cell that acts as a storage area |
| Digestive System | breaks down food and absorbs nutrients |
| Respiratory System | takes in oxygen and eliminates carbon dioxide |
| Reproductive System | the organs and glands within the body that aid in the production of new individuals |
| Circulatory System | transports materials to and from cells |
| Excretory System | removes waste |
| Immune System | protects the body from foreign substances such as infections |
| Muscular System | enables movement of the body and internal organs |
| Skeletal System | supports and protects the body |
| Endocrine System | controls many body processes by means of chemicals |
| Nervous System | detects information from the environment and controls body functions |
| Homeostasis | the process by which an organism's internal environment is kept stable in spite of changes in the external environment |
| Hormones | the chemical product of an endocrine gland that stimulate the activities of different organs and tissues |
