Populations in which reproduction within the group is encouraged are called: a. polygamous. b. bigamous. c. exogamous. d. endogamous.

The correct answer is D. Endogamous.

Explanation

Endogamous is a term used to refer to the practice of some group of individuals who radically rejects the incorporation of individuals outside their group or community. Also, this refers to an attitude of communities that prevent members of other groups from associating or joining in marriage, reproduction, or other relationships with members of their group.

This practice was very common in antiquity because it allowed power to be kept within the same family or to maintain the purity of a supposed race. So, the correct answer is D. Endogamous.

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.