Question

how are all atoms similar?
a. they are made up of the same types of particles.
b. they are the same size.
c. they cannot be divided.
d. they all undergo the same chemical reactions.

Explanation:

All atoms are made up of protons, neutrons, and electrons. Different atoms vary in the number of these particles, but the types of particles are the same. Atom sizes vary, atoms can be divided in nuclear reactions, and different atoms have different chemical - reactivity and undergo different chemical reactions.

Answer:

A. They are made up of the same types of particles.