HELP! Solar, biomass, geothermal, wind, and hydropower energy are all renewable sources of energy. They are called renewable because they: a. Are clean and free to use

b. Can be converted directly into heat and electricity

c. Can be replenished by nature in a short period of time

d. Do not produce air pollution

C. Can be replenished by nature in a short period of time

Explanation:

Renewable, as a word, means that it is able to be replaced again. Renewable energy is energy that is able to be replaced quickly, and will never run out. Solar, biomass, geothermal, wind, and hydropower energy all can be reproduced again without the risk of running out, unlike fossil fuels.

Hope this helps!

Panna

the right answer is it connects amino acids

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: