1. What is the relationship between a DNA molecule, a gene and a protein?

Explanation:

for example, one gene will code for the protein insulin, which is important role in helping your body to control the amount of sugar in your blood. Genes are the basic unit of genetics. Human beings have 20,000 to 25,000 genes.

Electromagnetic force

Explanation:

The attraction forces that causes the compression of the atom leading the to decrease in Atomic Radius is "Electromagnetic force".

Electrons (negatively charged) are strongly bonded with the nucleus (positive nucleus) by electromagnetic force. Electromagnetic force allows the electrosn to move in a specific orbit around the nucleus.

Atomic radius decreases from left to right in a periodic table because when valence electrosn are added at the same time the number of protons in nucleus increases. This increases the nuclear charge that attracts the electrons more strongly towards the nucleus and decreases the atomic radius.

Hence, the correct answer is "electromagnetic force".