A and B are biotic in nature, C, D, and E are abiotic in nature. In an open system, A produces D and E while B could not produce anything rather depend totally on the D and E produced by A. As the number of A increases, it favours the growth of B, the production of D and E also enhances the growth and development of B.

A: Plants

B: Consumers

C: Sun

D: Oxygen

E: food

Explanation:

Abiotic factors refer to non-living things int he ecosystem, whereas the biotic factors are the living things in the environment.

A, in this case, is referring to the plants in the ecosystem, the producers. Plants produce D and E, that is, oxygen and food respectively. B are the consumers in the environment, the herbivores in particular that feed on the plants and rely on it as the only food source. C refers to the sun as the source of light energy for the plants.