Biology Crossword Puzzle

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Across
  1. 2. system a decimal system of measurements whose units are based on certain physical standards and are scaled on certain physical standards and are scaled on multiples of 10.
  2. 5. a slight attraction can develop between the oppositely charged regions of nearby molecules.
  3. 8. proposed scientific explanation for a set of observations
  4. 9. cells that do not contain nuclei
  5. 10. organisms that make their own food
  6. 11. strong forces bind protons and neutrons together to form the ______
  7. 12. organisms that obtain energy from foods they consume
  8. 14. positively and negatively charged atoms
  9. 15. the science that employs the scientific method to study living things
  10. 16. the site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell
  11. 19. variable that is observed and that changes in response to the manipulated variable is called _______
  12. 22. cell is able to reproduce so that a group of cells.
  13. 23. portion of the cell outside the nucleus
  14. 24. an attraction between molecules of the same substance.
  15. 25. atoms of the same element that differ in the number of neutrons they contain.
  16. 27. a pure substance that consists entirely of one type of atom
Down
  1. 1. smallest unit of most compounds
  2. 3. small particles of RNA and protein found throughout the cytoplasm
  3. 4. variable that is deliberately changed
  4. 6. a substance that speeds up the rate of a chemical reaction
  5. 7. the process of gathering information about events or processes in a careful, orderly way.
  6. 13. forms when electrons are shared between atoms
  7. 17. a substance formed by the chemical combination of two or more elements in definite proportions.
  8. 18. devices that produce magnified images of structures that are too small to see with the unaided eye
  9. 20. cells that contain nuclei
  10. 21. an organized way of using evidence to learn about the natural
  11. 25. Bond/ formed when one or more electrons are transferred from one atom to another.
  12. 26. proteins that act as biological catalysts.