Question

the survivorship curves of the american robin, a type of migratory songbird, and the common green darner, a type of migratory dragonfly, are shown below. what statement is best supported by the survivorship curves? a. a very high proportion of common green darners reach adulthood and live to older ages. b. american robins have similar death rates throughout their lifespan, while the death rate of common green darners changes over their lifespan. c. younger american robins have higher death rates than older american robins, while younger and older common green darners have similar death rates. d. american robins have a high survival rate for most of their lifespan and then decline rapidly in old age.

Explanation:

The American robin's survivorship curve is a straight - line on a log - scale, indicating a relatively constant death rate throughout its lifespan. The common green darner's curve drops sharply at first, meaning high death rates among the young, and then levels off. This shows that American robins have similar death rates throughout their lifespan, while the death rate of common green darners changes over their lifespan.

Answer:

B. American robins have similar death rates throughout their lifespan, while the death rate of common green darners changes over their lifespan.