The y chromosome is believed to have evolved from the x chromosome by a series of steps, including all of the following except: a. suppression of crossing over, keeping the maleness gene associated with other male trait genes. b. mutations at other genes affecting male traits. c. a mutation on a proto-x chromosome causing maleness d. degeneration of other genes due to lack of crossing over. e. actually, all of these are proposed steps in the evolution of the y chromosome.

E. Actually, all of these are proposed steps in the evolution of the Y chromosome.

Explanation:

https://www.my46.org/intro/x-linked-inheritance

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.

the answer is trees if i'm not mistaken