What is the purpose for mitosis

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

What can be found in every skeletal muscle? a. nerves, bones, cartilage, and connective tissue b. tendons, cartilage, nerves, and blood vessels c. muscle fibers, nerves, connective tissue, and blood vessels d. tendons, nerves, blood vessels, and bones

In what for do plants utilize nitrogen? why do they need nitrogen?