What is an electron?
A. Where protons and neutrons are
found
B. The smallest part of an atom
C. A part of an atom that is positively
charged
D. The heaviest particle in an atom.

B. The smallest part of an atom

Explanation:

Electrons are the smallest of the three particles that make up atoms. Electrons are found in shells or orbitals that surround the nucleus of an atom. Protons and neutrons are found in the nucleus. They group together in the center of the atom.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.