Thomas malthus's contribution to natural selection is the:
a.
binomial taxonomic system of naming species.
b.
theory that the earth's old age is based on geologic evidence resulting from cataclysmic events.
c.
theory that environmental resources increase to population pressures.
d.
observation that an abundance of food would allow a population to increase geometrically and indefinitely, but there simply is not enough food, so populations are limited by food supply.