What is a plant cell that is a rodlike structure that supply energy to other parts of the cell?

Mitochondria...

Mitochondria are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy rich molecules for the cell. The biochemical processes of the cell are known as cellular respiration.

It is mitochondria, they are like the food that's supplies energy to all different parts of the cell.

Answer the lack of variation in activity can lead to boredom and eventually cause exercise to stop;