remaining questions to be answered!

why hot soup/food is more tasty than cold one?

why bread become green then black? why do it not turn black then green?

why wax shrink on heat? (opposite to normal things)

why fire does not work on the threads of asbestos?

how infra red rays help to read from burnt papers?

can we increase the speed of light? if yes then how .plz think then reply( i dont need the ans. NO)
i am not fully satisfied with earlier answer.