A porcupine has an internal skeleton and a rose has a stem. Write a sentence to explain how these physical structures have different functions.

What is the role of the phospholipid belayer in cellular transport in living cells

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

Explain the physiological changes that occur when the hypothalamus stimulates the sympathetic nervous system. you can make a flowchart or a simple step process. be sure to include all chemicals/hormones secreted, glands involved and the functions of each chemical/hormone.