Answer:
C. The number of protons an atom has defines what kind of element it is.
D. The basic unit of matter is the atom.
are the correct statements.
A is incorrect because the atomic number is the number of protons in an atom, which is different for different elements.
B is incorrect because an element is defined by the number of protons it has in its nucleus (which determines its atomic number), not the number of neutrons.
Step-by-step explanation: