Science Crossword

2. a particular substance that the body recognizes as foreign and that stimulates a response
3. a substance an organism needs to live
7. a type of blood cell that picks up oxygen in the lungs delivers it through out the body
8. a region of earth that has a particular climate and certain types of plants
9. a group of living things that are so closely related that they can breed with one another and produce offspring that can breed as well
11. a protein produced by some white blood cells to attack specific foreign materials
14. an organism that captures energy from sunlight and transforms it into chemical energy that is stored in energy-rich carbon compounds
15. the structures in the body that work together to transform the energy material in food into forms the body can use
16. a system that interacts with the environment and other body systems to bring oxygen to the body and remove carbon dioxide
18. an animal that other animals hunt and eat

1. a factor or condition that prevents the continuing growth of a population in an ecosystem
4. a process in which cells use oxygen to release energy stored in sugars
5. the first species to move into a lifeless area
6. the process of breaking down food into a usable materials
8. a fluid in the body that delivers oxygen and other materials to cells and removes carbon dioxide and other wastes
10. a living thing that gets its energy by eating other living things in a food chain
12. a small amount of a weakened pathogen that is introduced to the body to stimulate the production of antibodies
13. a series of events or actions that repeat themselves regularly
14. an animal that hunts other animals hunt and eats them
17. the scientific study of how living things interact with each other and their environment