How can natural selection account for the long tongues of butterflies?

Because butterflies with longer tongues were better equipped to eat nectar from inside flowers, and so it was easier for them to eat and grow. So they were better quipped to survive than those with shorter tongues.

a polymer is a chainlike molecule made up of small molecular units. these small molecular units are called monomers. monomers of polymer can be joined together either naturally or synthetically.  

b. to discover aspects of the natural world.

hopefully i .