What are two ways in which bacteria are useful

Creating products, such as ethanol and enzymes.

Making drugs, such as antibiotics and vaccines.

Making biogas, such as methane.

Cleaning up oil spills and toxic wastes.

Killing plant pests.

Transferring normal genes to human cells in gene therapy.

Some types of bacteria help you digest food. Others are used to create dairy products and even medicines. There are even some that prevent disease.

what school and grade?

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.