Final answer:
According to the Bohr-Rutherford model of the atom, a proton is 2000 times more massive than an electron and is located in the nucleus.
Step-by-step explanation:
The correct answer is A. A proton is 2000 times more massive than an electron and is located in the nucleus. According to the Bohr-Rutherford model of the atom, the nucleus is the small, dense, and positively charged center of an atom. It contains protons and neutrons. Electrons, on the other hand, orbit the nucleus in specific energy levels or shells.
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