How does natural selection lead to changes in organisms?

it is every organisms goal to "survive and repopulate" therefore, with natural selection the weaker organisms die because they did not possess the traits necessary to survive, and the strong survive and repopulate

Explanation:

not sure if this is what you'r looking for eubacteria and archaebacteria

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]