Question

what is an ecosystem?
the part of earth where all life exists
a system where living things interact closely with their environment
large areas within the biosphere characterized by their soil, vegetation, wildlife, and climate or weather
the set of chemical reactions that occur in living organisms in order to maintain life

Explanation:

An ecosystem is defined as a system where living organisms (biotic factors) interact with their non - living environment (abiotic factors).

• The first option “The part of Earth where all life exists” describes the biosphere, not an ecosystem.
• The third option “Large areas within the biosphere characterized by their soil, vegetation, wildlife, and climate or weather” describes a biome.
• The fourth option “The set of chemical reactions that occur in living organisms in order to maintain life” describes metabolism.

Answer:

A system where living things interact closely with their environment