Is body temperature interval or ratio scale? I understand that temperature is interval scale because it holds no true zero and can represent values below zero. But in case of body temperature it cannot go below a certain point and definitely not below zero. So in that case, will body temperature be a ratio scale?

Distinguish the proper from the measurable: The human body temperature is not bounded. Imagine a body found buried under deep snow (brrrr!), its temperature is obviously below zero. It is a measurable body temperature, and the same applies for extremely high temperatures (although at some point it'll decompose so somewhere there is an upper bound).
A proper body temperature is bounded, whether you put the interval as 36-38°C for strictly proper or you set it to 34-42°C to include most conditions of illness (such as hypothermia).
For both cases (measurable and proper), as there is no real "true zero". We know a general lower bound on temperatures which is Kalvin's zero, −273.15 °C, but it is not feasible so this is not a ratio scale.
