| A | B |
|---|
| Metabolism | total of all chemical activities in an organism |
| Homeostasis | ability of an organism to keep conditions inside its body the same, even though conditions in its external environment change |
| Element | pure substances that cannot be separated into simpler substances by ordinary chemical processes |
| Enzyme | chemical substance that helps control chemical reactions |
| Digestion | process by which food is broken down into simpler substances |
| Compound | two or more elements chemically combined |
| Spontaneous generation | hypothesis that states that life can spring from nonliving matter |
| Stimulus | signal to which an organism reacts |
| Asexual reproduction | reproduction requiring only one parent |
| Amino acid | building block of protein |
| Carbohydrate | energy-rich substance found in foods such as vegetables, cereal grains, and breads |
| Cell | basic unit of structure and function in living things |
| Sexual reproduction | reproduction usually involving two parents in which a sex cell from each parent unite to form offspring |
| Respiration | process in which simple food substances such as glucose are broken down and the energy they contain is released |
