Answer:
What sends oxygenated blood back to the heart from the lungs?
Oxygen-rich blood flows from the lungs back into the left atrium (LA), or the left upper chamber of the heart, through four pulmonary veins. Oxygen-rich blood then flows through the mitral valve (MV) into the left ventricle (LV), or the left lower chamber.
Explanation:
<span>A scientific theory must be testable and capable of being proven false. This is very important for these theories to be dealt with because they become the dependencies when they are applied for the analysis of the concepts and problem solving.</span>
<span>Diffusion. Diffusion is when particles in a highly concentrated area spread out to an area of lower concentration. The membranes of cells are very thin, which allows diffusion of different materials to happen easily.
During respiration, oxygen and glucose concentration in the cell is lower than in the surrounding blood. This causes oxygen and glucose to move into the cell via diffusion. Carbon dioxide is produced inside the cell and this makes the concentration of CO2 higher in the cell than in the blood, so the excess diffuses out of the cell.</span>
