Cells and Systems

2. The device used for viewing small objects.
5. The protective barrier that separates the cell interior from the environment.
7. A characteristic of a species that increases its chances of survival.
8. The production of offspring by a living thing.
12. The process by which plants convert sunlight into energy.
13. Different structures that perform similar functions.
14. The movement of particles from an area of high concentration to an area of low concentration.
16. The diffusion of water particles through a semipermeable membrane.
17. The control center of the cell that contains DNA.

1. A rigid structure that surrounds the cell membrane in plant cells.
3. The group of organs that perform certain functions to keep the organism alive.
4. The task carried out by a structure.
6. Part of an organism that performs specific tasks.
9. A balloon-like vesicle that stores water, food, and waste.
10. The process of increasing in size or developing.
11. The "powerhouse" of the cell that carries out cellular respiration.
15. The reaction of an organism to a stimulus.
18. The basic unit of life.