Why do the elements in a group all behave similarly

See the explanation below, please.

Explanation:

The elements of the periodic table that belong to the same group (each column) have similar physical and chemical properties. This is because they have the same number of electrons in their last electronic layer.

Example of electronic configuration of elements of GROUP IA:

Hydrogen: 1s ^ 1

Lithium: 1s ^ 2 2s ^ 1

answer; i believe that the correct answer is (a); a large rock being weathered by wind and rain;

coral.

explanation:

coral. many marine organisms that produce calcium carbonate shells or skeletons are negatively impacted by increasing co2 levels and decreasing ph in seawater.