What is echolocation used for in whales and dolphins?

Communicate and to navigate.

Explanation:

Echolocation. Toothed whales (including dolphins) have developed a remarkable sensory ability used for locating food and for navigation underwater called echolocation. Toothed whales produce a variety of sounds by moving air between air-spaces or sinuses in the head.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.