It happens to the alveoli of our lungs during the respiratory process.

Explanation:

Although they're microscopic, alveoli are the workhorses of your respiratory system. located at the end of bronchial tubes. When you breathe in, the alveoli expand to take in oxygen. When you breathe out, the alveoli shrink to expel carbon dioxide.

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Because when u get older and want to have a kid, u need to know the body parts, how to make it...basically how the reproductive system works for the future.

Explanation:

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