a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.
This is not chemistry but it's A, off top.
Economy - If there isn't a sustainable economy, it won't be able to support many people so instead they are limited.
Weather- If a place is too warm or too cold it can affect the population. The weather may be seen as harsh.
Government- If people are not agreeing with the government and are against, many will leave. They won't be able to withstand it.
Overpopulation- If there is too many people, they may restrict how many babies you can have and how many people can live there. China, a co
B. It is the heat required to change a gram of substance from solid to liquid
