A reptile must have a body temperature of at least 40.0 degrees Celsius (${}^{\circ }\mathrm{C}$) to become active. If the reptile has a body temperature of 37.5${}^{\circ }\mathrm{C}$, what is the minimum increase in body temperature, in ${}^{\circ }\mathrm{C}$, that it needs to become active?