We need to find mass number
Your answer is 40u
It's A, t<span>The figure is a molecule and an element.</span>
Answer: The closeness, arrangement and motion of the particles in a substance change when it changes state. Materials are a store of internal energy , due to the motion of particles and the chemical bonds between them. When a substance is heated, its internal energy increases: the movement of its particles increases.
Explanation:
Nucleus is the answer, I believe
