Define the components of blood and briefly describe their role.

Tha main components in blood are the plasma, red blood cells, white blood cells, and blood platelets.

Plasma is like the main component that makes up most of the blood. It has a light yellow color and it carries many substances including nutrients, waste, hormones and more.

Red blood cells are the reason why blood is red in color. They have a hemoglobin inside them which can help carry oxygen for the tissues and organs. In order to maximize the oxygen carrying capacity, they don't have a nucleus.

White blood cells can be divided into phagocytes and lymphocytes. Their main function is to protect us from diseases. Phahocytes and engulf and digest bacteria, while lymphocytes can produce antibodies.

Blood platelets can cause blood clotting which can stop us from bleeding forever. They're not cells, but just fragments of cells. They also don't have nucleus since they're not complete cells.

Processes above and be sure to mention the movement of electrons and energy as the carbon atom moves from one reaction to another.

It's either -limiting factors or -scarce resources but i'd go with my first answer since the food and water are abundant they really aren't scarce