This is the cycle of blood from being oxidated at the lungs to returning there for reoxidation:
Lungs - gas ❌.
02 blood to left atrium.
Through ❌ valve to the ventricle.
Through semi lunar valve to the ❌.
02 blood travels around the ❌.
Looses oxygen to muscles through ❌.
De02 blood to the heart.
Through the ❌.
De02 blood to the right ❌.
Through ❌ valve into the right ventricle.
Through semi-lunar valve into the ❌.
De02 blood to the lungs to be oxidated.

Diffusion and ❌ are both the movement of particles from a ❌ concentration to a ❌ concentration. Osmosis only happens in the movement of ❌. Both ❌ and osmosis can pass their particles through partially ❌ membranes.

❌, on the other hand, is the movement of particles from a low concentration to a high concentration. Active transport requires ❌. Plants and certain cells like cells in the ❌ use active transport to obtain and ❌ the ❌ they need. This is because there is often a higher concentration of nutrients ❌ the cell then ❌ it.