Final answer:
Scientists are studying the number of species in communities, population growth, and how nature works.
Step-by-step explanation:
Scientists are trying to find out all of the above: how many species live in a given community, how large a population can grow, and how nature works.
They study populations to determine their size, density, and distribution pattern, and use techniques like life tables and survivorship curves to calculate life expectancies of individual population members. When resources become limiting, populations follow a logistic growth curve in which population size will level off at the carrying capacity.
Scientists also study communities to understand how species interact with each other and compete for the same resources. The variety of species living in a given area is referred to as biodiversity.