Answer:
B
Explanation:
This is the First Law of Thermodynamics which states that energy cannot be created or destroyed.
It is either concave lens or mirror but since this is reflecting out rather than reflecting back it has to be concave lens. hope that helps! :’)
Washing your hands beforehand is important in order to minimize contamination of your experiments. This gets rid of things such as bacteria that can interfere with lab results. You should also wash your hands after completing lab because the chemicals you work with can leave toxic or harmful remains on you. It's important to wash those chemical traces off before you go outside the lab area.
