The covariance method of traditional inductive logic means that if only one situation changes in several occasions when the phenomenon under study changes, the only change is the cause or result of the phenomenon under study.
According to the above definition, which of the followings applies the covariance method?
In 1917, American physiologist Jacob and others found that when other conditions remain unchanged and the temperature changes normally, the life span of fruit flies can be doubled for every 8  degree decrease in temperature. It can be concluded that the life span of fruit flies is related to temperature.