Answer the following question given this paragraph: 

Clouds on Earth are made of water vapor. Venus's clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide, and large amounts of corrosive sulfuric acid! Scientists think the color of sunlight on Venus is reddish-brown.


Q: What are clouds on earth made of?

 Choices:

- rain

- ozone

- carbon dioxide gas

- water vapor

A:
water vapor
