B) Ecosystem - which includes the living communities and nonliving factors in an environment
<span>Humans add greatly to the carbon cycle by "</span>exhalation of carbon<span> dioxide, the burning of fossil fuels, deforestation and other poor agricultural practices."
-Reference.com</span>
The correct answer is B. tundra. Hope this helped.
Final Answer: Non-living factors
Explanation:
Abiotic factors are non-living factors in an organism's environment.
Examples: Lack of rainfall, Dry soil, Rivers dry up (air, water, sunlight, soil)
~I hope I helped you :)~