Can be a number of things, rain fall quota, climate, population, vegetation..any of those.
They would test two subject/mice which is S-Strain and R-Strain to see the differences and scientific behavior. In the end one died which is S-Strain and the other lived which he later affirm the transforming principle by testing with the chemical itself. In turn out comes the Answer
These are known as Hormones. Hormones are chemical messengers that are released in one tissue normally endocrine glands for example, adrenal glands, pituitary glands, and transported in the blood stream to alter the activities of specific cells in other tissues. Hormones serves as messengers, controlling and coordinating activities or processes such as growth, metabolism and fertility in the body.
Because if you take care of your body/organs by exercise and good diet then your bidy will stay healthy without sickness which results in longer life span
