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Across 1. The experimental factor that is manipulated(changed); the variable whose effect is being studied. 3. the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist 7. a partiality that prevents objective consideration of an issue or situation 8. a signal to which an organism responds 9. the variable that is measured in an experiment, the outcome factor; the variable that may change in response to manipulations of the independent variable The Variable that is measured 11. process by which organisms maintain a relatively stable internal environment 15. the instructions to make proteins 16. well-tested explanation that unifies a broad range of observations that has been throughly tested 17. the science that studies living organisms 18. an experiment in which only one variable is manipulated at a time 20. an organized way of gathering and analyzing evidence about the natural world. 21. a complex molecule containing the genetic information that makes up the chromosomes

Down 2. process by which a single parent reproduces by itself 4. a proposed scientific explanation for a set of observations in ways that support or reject it 5. process by which cells from two different parents unite to produce the first cell of a new organism 6. process of noticing and describing events or processes in a careful, orderly way 10. in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment. 12. logical interpretation based on prior knowledge and experience 13. set of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes 14. a testable statement 19. information gathered from experimental observations