As many of people know, talking, moving, and laughing too much can cause energy loss. However, the energy is not lost, instead it is returned back to nature as heat. But these days, we should try to use energy efficiently. Many attempts have been done to convert energy as efficient as possible.1. It is stated that energy cannot be lost, but can be converted. What law stated that?
2. Give three examples of energy conversion.
3. Paula's home uses electricity from the water powerhouse. One hot summer, the powerhouse cannot produce electricity for the river moving the generator can't work properly. Paula has a solar panel, a hamster and it's running wheel, and a treadmill. What will Paula probably choose to generate electricity for a while? State why.

I know that the points are quite bigger than usual, but you have to answer it properly. I am looking forward for your answer. It does not matter which language you answer this in, you may use any language you can. Thank you.