Science

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Across
  1. 3. Gradual change in species over time.
  2. 7. Proposed explanation made on the basis of limited evidence.
  3. 9. Subatomic particle with no electric charge.
  4. 11. Substance that increases the rate of a chemical reaction.
  5. 12. Variants of a particular chemical element with different neutron numbers.
  6. 15. Powerhouse of the cell, where energy production occurs.
  7. 16. Community of living organisms interacting with their environment.
  8. 17. Substance that stimulates the immune response to prevent disease.
  9. 19. Smallest unit of a chemical element.
  10. 20. Large naturally occurring community of flora and fauna.
Down
  1. 1. Study of heredity and variation in organisms.
  2. 2. Force that attracts objects toward each other.
  3. 4. Protein that speeds up chemical reactions in living organisms.
  4. 5. Process by which plants make food using sunlight.
  5. 6. Visible surface of the sun.
  6. 8. Set of life-sustaining chemical reactions in organisms.
  7. 10. Instrument for observing distant objects.
  8. 13. Fundamental particle making up protons and neutrons.
  9. 14. Combination of two or more atoms bonded together.
  10. 18. Thread-like structure carrying genetic information.