Why are changes in the global carbon cycle important? i) burning reduces available carbon for primary producers and, therefore, primary consumers. ii) deforestation and suburbanization reduce an area's rate at which energy is stored as biomass by plants or other primary producers and made available to the consumers in the ecosystem. iii) increasing atmospheric concentrations of carbon dioxide could alter earth's climate.

iii) Increasing atmospheric concentrations of carbon dioxide could alter Earth's climate

Explanation:

Increased concentration of carbon dioxide traps heat in the earth or insulate the Earth leading to increase in temperature of the Earth. Example of the effect is retreating polar ice caps as a result of melting. Having an understanding of the release and absorption of carbon dioxide, one of the green house gases,  is important to predict global warming trends and understand the climate. Other examples of green houses gas include water vapor, methane, CFC, nitrous oxide and others

the answer is 1 i believe