Question

why does the amount of water vapour decrease rapidly with altitude

Answer 1

Water vapours are the gaseous state of water that gets evaporated from the leaves of plants in high temperature. So, to be in gaseous state, they need a high temperature. As we go up the altitude, the temperature decreases due to the increase in pressure. As mentioned above water vapours need high temperature to be in gaseous state. But the increase in temperature at high altitude change their state to liquid, which we see as rain.

Answer 2

Explanation:

its the answer from middle