Answer:

1. C

2. C

3. A

4. A

Explanation:

THIS IS BASE ON MY RESEARCH:)

Answer:

1. C. Biotic factors

2. C. Oxygen, rock, sunlight, water

3. A. An empty aquarium

4. A. Ecosystem

Explanation:

1. Biotic factors are things that are living things. Humans, plants and animals are biotic factors of the environment.

2. Oxygen, rock, sunlight, water are abiotic factors because they are non-living things. Even they are abiotic components, they still help our environment.

3. An empty aquarium doesn't show an ecosystem. The other choices does since they have biotic or abiotic factors in it.

4. An ecosystem is where biotic and abiotic interacts. (See the picture above. Sunlight, heat, trees, soil, water, rotting log and bush are the abiotic factors. Insects, frog, bird, fish, snakes and bacterias are the biotic factors)