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:

Statement 1 is correct because water vapour is concentrated in the lower troposphere and its quantity decreases rapidly with altitude — nearly all atmospheric water vapour is found below 5 km. Statement 2 is incorrect because the percentage of water vapour is maximum at the equator (humid tropics), where it can be up to 4% of the atmosphere, and minimum at the poles where cold air holds very little moisture (often less than 0.1%). Thus only statement 1 is correct.