Do we need energy when we sleep ? Why/why not ?

Do we need energy while sleeping?

We need energy while sleeping to maintain

When we go on a busy road, feel uneasy even when we close nose with a napkin. Why these symptoms we observe?

What does food give us? Why is it necessary when we sleep?

What do you mean by the term 'Science' ? Why do we need it ?

Why do bubbles appear in water when we heat it ?

Why do we need proper drainage system?

How do we know that we need food ?