Ecosystems

2. Relationship between two organisms living closely together, where each benefits the other
3. Relationships between organisms, where each affects the other's survival
7. Relationship between organisms that are trying to use the same limited resource
8. Relationship between two organisms, where one organism kills and eats the other
9. Relationship between two organisms, where one organism lives on or in the other and feeds off it
12. A non-living factor of the environment
13. All the living organisms in an ecosystem

1. A place where organisms and their physical surroundings form a balanced environment that is different from others nearby
4. All the factors in an organism's surroundings that affect it
5. Relationship between two organisms, where one benefits and the other is unharmed
6. Where an organism lives
10. A living factor of the environment
11. The study of how organisms interact with each other and their environment