What are the three main purposes for which water is used in industry?

It is hard to guess what the expected answer to this must be when the "industry" is not defined. It is also hard to know exactly what "main purpose" means. Some might consider the main purpose of water to be to keep the workers hydrated since dead workers tend to slow an industry. If your industry that you have in mind is farming then to the following list, you will want to add "provisioning crops and livestock". The best answer will come from your notes you took in class.

• Energy transfer (heating and cooling)
• Washing and rinsing
• Transportation