Hurry: which describes why radioisotopes can be used as tracers in studying the biological and chemical processes of plants?
the radioisotope is chemically identical to the nonradioisotope the plant normally uses
the radioisotope is absorbed more quickly than the nonradioisotope the plant normally uses,
the radioisotope converts the nonradioisotope normally used by a plant into a radioisotope.
the radioisotope travels through the plant without participating in any chemical processes