Answer:
3. biological hazard
Explanation:
Any hazard that can be carried around the world and spread through contact can be spread quickly, specially owing to the mobility of humans. Noninfectious diseases cannot be transferred via human mobility as it is noninfectious. Chemical hazard require the chemical to be physically transported without the need for human itself. Physical hazard, as well, require the hazard to be transported or travel on its own without the influence or interference of humans. Biological hazard can be transmitted via human body as they become the carrier of the hazard.
The main reason would be the environment because of the fact their population is so big, they need enough room for everyone. There's also the connection with having available food source within the environment when the people plan to settle in. There's also the idea of desirable climate which helps them with food sources and allows them to flourish instead of dying off.
Explanation:
D. because it is a system of beliefs a religion is a system of beliefs with followers