Question

1. which of the following must be present in order to have a healthy ecosystem?

a. more animals than plants
b. enough basic needs for each biotic factor
c. an atmosphere of mostly carbon dioxide
d. only abiotic factors

Explanation:

• Option A: In a healthy ecosystem, there isn't a requirement for more animals than plants. Plants are primary producers, and the balance between different organisms (not just more animals) is crucial.
• Option B: For a healthy ecosystem, each biotic factor (living organisms like plants, animals, fungi, bacteria) must have its basic needs (such as food, water, shelter, suitable temperature range) met. This ensures the survival and proper functioning of all components within the ecosystem.
• Option C: The Earth's atmosphere is mostly nitrogen (\(N_2\), about 78%) and oxygen (\(O_2\), about 21%), with a small percentage of carbon dioxide (\(CO_2\), around 0.04%). An atmosphere mostly of carbon dioxide would not support most life - forms as we know them.
• Option D: An ecosystem consists of both biotic (living) and abiotic (non - living, like soil, water, air) factors. Only having abiotic factors cannot form an ecosystem.

Answer:

B. Enough basic needs for each biotic factor