Ecologists use survivorship curves to visualize how the number of individuals in a population drops off with time. By plotting the number of survivors per 1,000 individuals on a log scale versus time, three basic patterns emerge, seen here in the graph. Type III survivorship is best explained by which statement? A) The mortality of an individual does not depend on its age. B) Heavy parental investment improves competitive ability and makes it more likely that individuals will survive to reproduction. C) Much effort is invested in each individual, resulting in high survivorship throughout the life cycle. Most individuals die of old age. D) Many thousands of offspring are produced, most of whom die right away. Once this period is over, survivorship is relatively constant.