Why most of the livingthings sleep at night and work at day time? Why is it not in the reverse order?

Answer 1

Because there is a huge source of electromagnetic radiation in the daytime sky (the sun) which can be used to gather a lot of information about the surrounding environment because of a very early evolutionary development called "vision".

Vision was such a useful development that nearly all mobile species make use of it. Animals with especially senstitive vision can make use of available light at nighttime and take advantage of fewer competitors and predators at that time.

Answer 2

everything needs sunlight to survive