Vocabulary

1. electromagnetic radiation that lies within the visible range.
4. energy created by moving charged particles
9. the layers of gas that surround Earth, other planets, or stars.
10. one of the fundamental states of matter with a definite volume but no definite shape.
12. an integrated unit of a biological community, its physical environment, and interactions.
13. a vent or fissure in Earth's surface through which magma and its associated materials are expelled; generally a mountain-like structure.
16. the observed effect of the force of gravitation.
18. a star pattern identified and named as a definite group.
19. an animal or plant that consumes or obtains nutrients from animals.
20. having a definite shape and a definite volume; one of the fundamental states of matter.

2. an animal that feeds on plants.
3. the smallest unit of a chemical element.
5. a procedure that is carried out in order to observe a response caused by a stimulus.
6. the process of changing from a gas to a liquid; the act of making more dense or compact.
7. a whole or part of a plant or animal that has been preserved in sedimentary rock.
8. a large collection of stars, gases, and dust that are part of the universe.
11. the bouncing off or turning back of light, sound, or heat from a surface.
14. a structure containing different tissues that are organized to carry out a specific function of the body.
15. a large, gaseous, self-luminous body held together by gravity and powered by thermonuclear reactions.
17. one of the fundamental states of matter in which the molecules do not have a fixed volume or shape.