Why don't we run out of the important gases that we need to stay alive?

The reason why we don't run out of the important gases that we need to stay alive is due to existence of the natural recycling processes such as the carbon cycle and oxygen cycle makes use of gases produced by living organisms, which are carbon dioxide and oxygen to reproduce the gases used

The important gases we need to stay alive are;

The aerobic respiration and photosynthesis processes along with other natural occurring processes through which oxygen and carbon dioxide are produced  creates a cycle that sustains the gases that we need to stay alive so that they do not run out

The cycles are known as the carbon and oxygen cycles

Learn more about the carbon and oxygen cycles here:

link

the most common energy conversion is from kinetic energy to potential energy, and then from potential energy to kinetic energy.

later on comes the heat energy, mechanical energy, and other energy conversions.

this energy conversion is so common that we can find it in our day to day lives as well.

- one of the most common energy conversions involves the changing of potential energy to kinetic energy or kinetic energy to potential energy

the answer would be..

b. sucking