That’s not universally true. I know several people with PhD who have encyclopedic knowledge completely outside their specialisation. Some people are just super intelligent, talented and have enormous memory. The world is not fair.
Not really. Babies have brown fat as default. Adults have white fat which can turn brown in response to cold exposure (not as much as in babies, so it’s also called beige fat). Brown of beige though, it works the same - there’s a high count of mitochondria in the cells and the tissue can produce heat and make you feel (and be) warmer. It also helps with weight loss, stimulates the immune system and lowers inflammation.
Don’t fixate on the alien part. That part is not supposed to be realistic, because it doesn’t really represent aliens - it represents us people.
It’s the same kind of alien trope used in Star Trek to represent different aspects of humans. It’s not what aliens would probably really be like (trully alien).
It’s a tool for illustrating human behaviour and it works decently well.
Fortunately, we’re doing our best to make our life conditions harder in the future and possibly to lower the population as well!
Of course, there can be other sets of conditions that lead to kindness win. Like probably heavy cultural persecution of selfishness. The conditions can also be pretty complex. I wonder whether those things have been studied in some meaningful way.