What does it mean to move UP the concentration gradient?

"Up" or "against" a concentration gradient means from low concentration to high concentration. Moving in this direction requires some sort of energy input, such as active transport using ATP, or an electrical gradient, or something else.

Explanation:

If this helps, is it possible to give me brainliest please?

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.

the electromagnetic energy from the sun arrives in the form of visible and invisible light.