With reference to "water vapour”, which of the following statements is/are correct?

1. It is a gas, the amount of which decreases with altitude.
2. Its percentage is maximum at the poles. Select the answer using the code given below:

Water vapour is a variable gas in the atmosphere.

The amount of water vapour decreases with altitude.

In warm, wet tropics, water vapour can constitute up to 4% of the air by volume. Conversely, in dry, cold desert and polar regions, it can be less than 1%.

Water vapour also decreases from the equator towards the poles.

Water vapor absorbs solar insolation and traps Earth's radiated heat, acting as a blanket to regulate Earth's temperature.

Statement 1 is correct. Statement 2 is not correct.

Hence, only statement 1 is correct.