Ivy starts to get into the hot tub, but the water feels extremely hot. She stands in the water for a few moments, then slowly eases the rest of her body down into the water. After a few minutes, she feels quite comfortable; the water no longer feels too hot. This decline in sensitivity to a constant stimulus that Ivy has experienced is called:

sensory adaptation

Explanation:

Sensory adaptation occurs when our senses no longer percieves a stimulus because of our sensory receptor's continuous contact with it.

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.