Concept:Population growth is driven by demographic factors like birth and death rates, not by physical environmental conditions.
Explanation:Climate, relief, and soil fertility are physical factors that affect population distribution and settlement patterns.
They do not directly control the rate at which a population increases or decreases.
Birth rate is a direct and measurable component of population growth.
A higher birth rate means more new individuals are added to the population over time.
If the death rate remains constant, an increase in birth rate leads to faster population growth.
Therefore, among the given options, birth rate is the key factor directly causing population growth.
Answer:C. Birth rate