What is an index fossil?
A. A fossil that contains rocks and minerals
B. A fossil found in rocks from one time period
C. A fossil that formed 300 million years ago
D. A fossil that has vestigial structures

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.

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it

occluded front i think