A. The connective tissues that protect the inside of the arteries and veins.
Some of the organisms have evolved in such a way that they remain inactive when the predator populations are active.
Adaptive theory of sleep suggests that the prey population prefer to sleep when (in this case, at night) the predators are most active. The prey population use this time in taking rest and restoring energy for other works. As the prey population is inactive and remained protected in safe places, they are less likely to be predated.
Hence, the correct answer is adaptive theory of sleeping.
