Is the source of almost half of all renewable energy in the united states.

Explanation:

Renewable energy in the United Stated is mostly sourced from Biofuel with an 22.4% of all renewable sources used.

Biofuel comprehends fuels that are made from organic material, exactly, biomass.

Biomass is plant or animal material used as energy, like forest residues or animals waste.

trachea, alveoli, lung capillaries, arteries

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.