What is an ecosystem?

a biological community of interacting organisms and their physical environment.

"the marine ecosystem of the northern Gulf had suffered irreparable damage"

(in general use) a complex network or interconnected system.

"Silicon Valley's entrepreneurial ecosystem"

Explanation:

An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. ... Abiotic factors include rocks, temperature, and humidity.

The array of living organisms found in a particular environment together with physical and environmental factors that affect them is called ecosystem.

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%