PLEASE HURRY ITS URGENT

Chemicals usually bond in such a way to follow the octet rules. This rule is best describe by which of these
)
A
Atoms bond so each atom has exactly eight electrons in its shells.
B)
Atoms bondso that they have eight electrons in every shell of each atom.
Atoms bond so all the protons and electrons are in balance after the
bonding process
Atoms bond by transferring or sharing electrons to fill the valence shell
and obtain noble gas configurations,

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.

it would lead to upper respiratory infections and pneumonia.