calcium
Calcium (Ca)
Calcium is the answer. Atomic weight 40 - with 20 protons means 20 neutrons. Calcium is a key element in teeth and bones.
calcium
Calcium
You are calcium. Most calcium atoms have 20 neutrons though 20 - 28 is possible, but it is the fact that they have 20 protons which makes them calcium.
Calcium has 20 neutrons and is found in your teeth.
20 teeth
Calcium
20
20
This element is calcium.
20