The answer is A. Proton. Protons have the opposite charge to electrons, which have negative charges.
Answer:closed systems
Explanation:
A closed system is one in which matter does not enter or leave the system but there is exchange of energy between the system and its environment. In a closed system, the principle of energy conservation applies. The principle of energy conservation states that energy can neither be created nor destroyed but is converted from one form to another. An example of a closed system is a reaction vessel whose lid is closed.
Formula from physics to get the answer.
