What differs from between a radioactive isotope and a stable isotope

A stable isotope has just the right number of neutrons for the number of protons (the n:p ratio) to hold the nucleus together against the repulsions of the protons.

A radioactive isotope has either too few or too many neutrons for the nucleus to be stable,

The nucleus will then emit alpha, beta, or gamma radiation in an attempt to become more stable.  

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.