Answer:
The circulatory system has evolved over time from simple diffusion through cells, in the early evolution of animals, to a complex network of blood vessels that reach all parts of the human body. Made of specialized and unique cardiac muscle, it pumps blood throughout the body and to the heart itself.
Claps shut at birth. Evolutionary changes in the vertebrate heart are tied to change from single to double-circuit heart, with increased separation of oxygenated and deoxygenated blood, allowing more efficient respiration and circulation to fuel high activity and increased oxygen demands associated with endothermy.
Answer:
Diffusion
Explanation:
Substances like CO2 and water move into and out of a cell by diffusion from an area of high concentration to an area of low concentration.
The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.
Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton<span>, which form a system of scaffolding that maintains cell shape. Other proteins are important in cell signaling, immune responses, </span>cell adhesion<span>, and the cell cycle. hope that helped</span>
