Feedback for subjective question

Question 1: Read the following text and state the main idea of the passage.
To many parents, the infant's crying may be mainly an irritation, especially if it continues for long periods. But crying serves important functions for the child as well as for the parents. For the child, crying helps improve lung capacity and the respiratory system. Perhaps more important, the cry serves as a signal of distress. When babies cry, they indicate that they are hungry or in pain, and this is important information for parents.