Which statement best describes the variables in a controlled experiment?
a. the independent variable is changed to see its effect on the dependent variable while all other conditions are unchanged.
b. the dependent variable is changed to see its effect on the independent variable while all other conditions are unchanged.
c. the independent variable is allowed to change, and the dependent variable is held constant to see what other conditions show a relationship.
d. the dependent variable is allowed to change, and the independent variable is held constant to see what other conditions show a relationship.

Listenbase your answer to the question on the information below.nuclear radiation is harmful to living cells, particularly to fast-growing cells, such as cancer cells and blood cells. an external beam of the radiation emitted from a radioisotope can be directed on a small area of a person to destroy cancer cells within the body.cobalt-60 is an artificially produced radioisotope that emits gamma rays and beta particles. one hospital keeps a 100.0-gram sample of cobalt-60 in an appropriate, secure storage container for future cancer treatment.which choice represents the correct product for the beta decay of the co-60? fe-60ni-60fe-61ni-61