Near the equator cause if you go to far south then it starts getting colder
Humans are social animals so conversation is necessary to keep a human away being lonely which can lead to compression then death
They have different specifications eg. a muscle cell has lots of mitochondria as it needs to do a lot of work, or a neuron has to have a mylin sheath to insulate signals
The Mitochrodria helps break down sugar and turns it into energy