Which of the following statements about change in ecosystems is true?
a. ecosystems experience change through human activity only.
b. ecosystems experience change through natural events only.
c. ecosystems experience no change.
d. ecosystems experience change through human activity and natural events.

The correct answer would be d. Ecosystems experience change through human activity and natural events.

Ecosystem refers to a community consisted of all the living organisms (biotic component), their surroundings (abiotic component), and their interaction with each other as well as with abiotic component in a given area.

The biotic and abiotic components of an ecosystem are mainly connected through energy flows and nutrient cycles.

Both components can affect the ecosystem in positive as well as negative manner.

Thus, both human activities (such as deforestation, pollution, sustainable development), as well as natural events (such as earthquake, tsunami, forest fires), can affect the ecosystem.

c is the answer to this question. altitude affects the weather because air molecules evaporate.