Each year as the weather gets cold, gray whales swim over 10,000 miles from arctic waters south to coastal areas of northern Mexico. After their young are born, they return to the Arctic.

The whales are responding to an
stimulus.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

d

explanation: