The extremes of dry and wet weather of the galapagos islands cause the food supply to constantly change.
during dry years, the food is mainly large, hard seeds, and finches with large beaks are found in greater
numbers.
which statement best explains this observation?
(1) dry environments cause mutations in finches.
(2) finches grow larger when they have more water.
(3) small finches become smaller during dry seasons.
(4) large beak size is an adaptation to dry conditions.

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.

your answer is "the 1950's"