I don't understand this. if they anyone that can help i would be grateful

How does a hydroelectric power plant converts energy into energy.

Adilute aqueous potassium nitrate solution is

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a.the mitochondria b.the nucleus c.the vacuoles d.the endoplasmic reticulum