Compared to mammals in colder climates, mammals that live in very hot, dry ecosystems tend to
have adaptations that include which of the following?
Z. Larger, thicker bodies to avoid heat loss to the air.
Y. A denser covering of hair for insulation.
X. Mechanisms and habits that limit water loss.
W. A diet that includes a wide variety of foods.

X. Mechanisms and habits that include limit water loss.

Explanation:

Many mammals that live in dry ecosystems tend to have above adaptations because there is a shortage of water in these areas. And of course water is the most essential thing for survival.

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.

b is the best answer for this question.