The inference about the effect of CO₂ and temperature on the rate of photosynthesis are:
(i) For most of the plants, temperature above \(40^oC\) result in creased rate of photosynthesis upto a limit.
(ii) Increase in the concentration of CO₂ results in increased rate of photosynthesis upto a limit.

The human activities like deforestation, over-cultivation, unrestricted grazing, poor irrigation practices, result in arid patches of land (deforestation). When these large barren patches extend and remain unattended for long, a desert is created. Because the formation of fertile top layer of soil takes millions of years, desertification easily takes over.

Carbon dioxide is a major greenhouse gas. Various human activities such as combustion of fossil fuels, electricity generation, transportation and industries are sources of its large scale production. Excess of CO₂ is harmful and considered as a pollutant. It is because it traps longer wavelength IR radiations reflected by earth's surface, thus causing global warming.

Species diversity is the occurrence of variety and abundance of species in community while ecological diversity is the occurrence of different ecosystem and communities in a geographical area.

Hot spots bear major number of endemic species through having the area 2 % only. Thus by protecting hot spots, rate of extinction of species can be reduced up to 30%.