The Giraffe, as the Tallest Living Land Animal, Has Several

The giraffe, as the tallest living land animal, has several adaptations for its height.To prevent blood from pooling in the head when it bends down to drink, the jugular veins of a giraffe have multiple one-way valves.Furthermore, a web of arteries and veins in the neck called the rete mirabile ("wonderful net") slows the flow of blood into the brain.These specializations of the ______________________ act as mechanisms to maintain ______________________.

A) nervous system; homeothermy
B) nervous system; temperature homeostasis
C) circulatory system; blood pressure homeostasis
D) circulatory system; pH homeostasis