Kingom bacteria can be subdivided into 2 seperate groups based on the reaction with gram stain. The difference in this reactive relates to a difference the

Peptidoglycan layer

Explanation:

Based on gram stain, bacteria are classified as:

- Gram positive, having thick Peptidoglycan layer that retains more dye/stain after being rinsed by alcohol. Examples are staphylococcus Aureus, Clostridium etc

- Gram negative, having thin Peptidoglycan layer that retains less dye/stain after being rinsed by alcohol. An example is Escherichia coli

Thus, the difference in Peptidoglycan layer helped group bacteria into two