Ignoring migration, the age structure of a human population likely to increase in size will have what shape? - pyramid- both a pyramid and a rectangle tapering toward the top result in a population that increases in size.- a rectangle tapering toward the topinverted pyramid- both an inverted pyramid and a rectangle tapering toward the top result in a population that increases in size.

Pyramid, both a pyramid and a rectangle tapering toward the top result in a population that increases in size.

Explanation:

In age structures, there are four main diagrams, depending if the population of men and women has a rapid growth, a slow growth, stable or a mixing of them.

In most parts of the world, population of different countries present a constant  grow.

At the top of the graphic since is the representation of the old people, in a population, there will be less individuals with this characteristic. That is the reason of the decrease.

Hope this info is useful.