How does phone use before bedtime affect sleep What is the independent variable & dependent variable?

How well do different plant species tolerate salt water?

What is the independent variable & dependent variable

phone use before bed time can effect your sleep schedule and not only that, it will effect the way you think in a slower way because you used it too much before bed. It will drain your mind of energy and it is unhealthy to use electronics for more than 45 minutes.

Explanation:

there is no short story here so that i can answer the question.