Answer: C. the relative contributions of genes and environment in a population
Studying close relatives makes it easier for behavioral geneticists to single out the contributions of environment and genes in a population. Due to differences in genetic factors, differences occur between individuals and this in turn adds to the increase of the human population. The environment’s capacity to provide all the resources for the thriving of creatures within normal limits is greatly determined by the population of the area. Due to the limited availability of the resources produced, environmental problems occur when the population exceeds the limit. Competition in natural resources utilization, scarcity of natural resources, and the emergence of population are all problems that can occur when the population exceeds the limit of the resources produced.