When you eat food _ regulate the chemical reactions within your body that turn food into nutrients

Enzymes

Explanation:

Enzymes are biological catalysts, which regulate various chemical reactions in the body.

The biochemical reactions involved in the digestion of food are regulated by enzymes. These biochemical reaction converts food into nutrients that are useful to the body.

For instance, the enzyme amylase catalyses the hydrolysis of starch into sugars.

Keeping the earth spinning on its axis.
the moon acts as a stabilizer and keeps the earth from tumbling over. had it not been for the moon, the earth would see radical climate changes over short periods of time making evolution of life difficult.