Environmental Science Ecosystems and Ecology

Question 1

Which term describes all living organisms and their physical environment interacting as a system?

Accepted Answer

Ecosystem

Answer

An ecosystem includes both the biotic (living) and abiotic (non-living) components interacting together.

Question 2

What is the primary source of energy for most ecosystems on Earth?

Accepted Answer

Sunlight

Answer

Sunlight is captured by photosynthetic organisms and forms the foundation of most food webs.

Question 3

Which trophic level consists of organisms that convert solar energy into chemical energy?

Accepted Answer

Producers

Answer

Producers (plants, algae, cyanobacteria) fix solar energy via photosynthesis and form the base of the food chain.

Question 4

The process by which nitrogen-fixing bacteria convert atmospheric N₂ into ammonia is called:

Accepted Answer

Nitrogen fixation

Answer

Nitrogen fixation converts inert atmospheric nitrogen gas into biologically available ammonia (NH₃).

Question 5

Which ecological concept describes the variety of species in a given area?

Accepted Answer

Biodiversity

Answer

Biodiversity refers to the variety and variability of life forms in a specific habitat or region.

Environmental Science Practice Test