Energy refers to energy sources (such as solar, wind, and hydroelectric) that release very small amounts of greenhouse gases.

The correct answer would be renewable energy.

The renewable energy refers to the energy sources which gets replenished in nature at the same or similar pace at which they are being utilized by the humans.

They are also considered as clean energy sources as they produce no or least amount of pollution, greenhouse gases et cetera.

Examples may include solar energy, tidal energy, wind energy, et cetera.

one of the most common forms of pain or discomfort we feel during strenuous exercise is a burning sensation in our lungs or muscles that goes away shortly after we cease the activity. this is caused by a build-up of lactic acid.

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added