Scientists have long struggled to understand how snakes, which lack external ears, sense sounds. Now, a new study shows that sound waves cause vibrations in a snake's skull that are then “heard” by the inner ear. ... It was still unclear, however, whethersnakes could hear sounds traveling through the air.
Hope it may helps you
I told u as much as I can .....
because the outermost electron shell of atom of these gases is full, do not react chemically with other substances except under certain special conditions .noble gases are known as inert gas.the noble gases are not reactive. is because have little tendency to gain or lose electrons.