Social, cultural and economic factors influence fertility, mortality and migration rates. Migration is affected by various factors like age, sex, marital status, education, occupation, employment etc. Age and sex are main demographic factors that affect the migration.
The main continent would be South America. Llamas originated in North America, then migrated south to South America, and inhabited what is now Peru.
Answer:
The use of fertilizers
Explanation:
Eutrophication simply implies the increase in nutrient or nutrient enrichment.
Commonly, waterways are connected to other water bodies. When water from farmlands washes fertilizers into them, there is an increase the available nutrient. Overtime, the water can be oversaturated with nutrients and this would lead to eutrophication. We can attribute eutrophication to human activities.
Answer: Dormancy
The phenomenon wherein the leaves of the plants turn red and fall during the autumn season followed by the defoliation of trees is a concrete example of dormancy. Dormancy refers to the time wherein plants don't grow and wait for necessary environmental factors like moisture, temperature and others.