Across
- 1. A large ecological community, like a desert or tundra
- 3. Essential gas for respiration and combustion
- 6. A chemical element essential to life
- 12. Force that attracts objects toward the center of the Earth
- 14. A small rock or particle that enters Earth’s atmosphere
- 15. The control center of a cell, contains DNA
- 16. A chemical element, commonly used in disinfectants
- 18. A group of atoms bonded together
- 19. Carries genetic information
- 22. Capable of being decomposed by microorganisms
- 24. Relating to feeding or nutrition in an ecosystem
- 25. The study of heredity and gene function
- 27. A watercraft capable of underwater operation
- 29. A group of organisms capable of interbreeding
- 32. A state of matter where electrons are free from atoms
- 34. Kingdom of organisms that includes yeasts, molds, and mushrooms
- 35. The basic structural and functional unit of life
- 36. A cold-blooded vertebrate with scales, like snakes and lizards
- 37. Preserved remains of ancient organisms
- 38. An animal without a backbone
- 41. A small icy body that orbits the sun
- 42. The most abundant element in the universe
- 44. A rupture in Earth's surface through which molten lava erupts
- 46. Relating to the Sun
- 49. Force caused by moving electric charges
Down
- 2. Waves of energy, including light and radio waves
- 4. A celestial body that orbits a star
- 5. A microscopic infectious agent that requires a host cell to reproduce
- 7. Gas essential for respiration
- 8. The visible surface of the Sun
- 9. A molecule made of three oxygen atoms, protects Earth from UV radiation
- 10. Basic unit of matter
- 11. Organelle in plant cells responsible for photosynthesis
- 13. Green pigment in plants that absorbs light for photosynthesis
- 17. Microscopic organisms that can be harmful or beneficial
- 20. Process by which plants make food using sunlight
- 21. Warm-blooded animal with hair and the ability to nurse its young
- 23. Extended period of abnormally low rainfall
- 25. A large mass of moving ice
- 26. A large ocean wave caused by an underwater earthquake
- 28. A small rocky body orbiting the sun
- 30. The process by which organisms change over generations
- 31. The study of interactions between organisms and their environment
- 33. Simple organisms that perform photosynthesis in water
- 39. A dense forest found in tropical areas
- 40. A biological community of interacting organisms and their environment
- 43. Subatomic particle found in the nucleus with no electric charge
- 45. A substance that kills or inhibits the growth of bacteria
- 47. Instrument used to observe distant celestial objects
- 48. A closed path through which electricity flows