c. Factors 1 and 2 may be influenced by both nature and human factors
Explanation:
The sea level rising and the change in the atmospheric gases are both processes that are influenced by the nature, as well as by the human activities. Naturally, the earth has its own cycles, known as Milankovich cycles, through which the Earth warms up, or cools down, resulting in change of the atmospheric gases, and in accordance to that, change in the sea levels depending on the global climate. The humans to have become a big factor in the past few hundred years. The reason for that is that the humans with their activity started to release lot of greenhouse gases into the atmosphere, especially CO2 and methane. That has been changing the composition of the atmosphere, and the temperatures have been rising. The higher the temperatures, the more ice is melting around the poles and on the high mountains, resulting in an increase in the sea levels.
