5.
all organisms that sexually reproduce exhibit behavior that prompts reproductive activities with the opposite sex. why would this form of behavior most likely be naturally selected?

Behavior which encourages reproduction is favored

Explanation:

Sexual selection is also a form of natural selection. In sexual selection, an individual belonging to one sex is attracted to mate with individual belonging to other sex. Also, this leads to sexual competition among members of the same species to attract the attention of opposite sex member giving rise to intrasexual selection

As per the analysis of Darwin, males usually struggle between themselves to get an access to females.  

i think its the first one

supercell thunderstorms are perhaps the most violent of all thunderstorm types, and are capable of producing damaging winds, large hail, and weak-to-violent tornadoes