What do all elements in a column in the periodic table have in common?
their atoms have the same number of valence electrons.
their atoms have the same atomic mass.
their atoms have the same number of protons and electrons.
their atoms have the same number of neutrons.

Option A

Explanation:

The elements are arranged in a periodic table based on their properties. The group of similar elements share common characteristics and hence kept in the same periods.

The elements having same number of valence electrons in their outer shell. As they have same number of valence electrons they have similar properties in terms of reactivity, stability, et cetera.

Hence, the correct answers is option A

i believe it is c: genes for body color and wing size are inherited separately from each parent.

its probably to later but whats the question