Is this a multiple choice? Anyways I will just give you a written answer and hopefully it helps.
A: Helium is made up of two electrons held by electromagnetic force to two protons that are inside of a nucleus along with one or two neutrons.
Answer:
H₂O (water)
Explanation:
The reaction given is the glucose combustion inside the cells. During the combustion, it will be formed carbonic gas, water and energy.
The oxygen molecule is split in their two atoms of O. The element which has 1 proton and 1 electron is the hydrogen (H). So, when hydrogen reacts with oxygen, they form water (H₂O).
Answer:
The atomic number is the number of protons in the nucleus