<span>The horizontal line present across the front teeth are called perikymata. These are incremental growth lines that appear on the surface of tooth enamel as a series of linear grooves. These lines can be used to assess how long the crown of the teeth formed. </span>
<u>Option-(B):</u> The following is not an observation or inference on which natural selection is based is the characteristics of a poorly adapted individuals which can never produce offspring.
Explanation:
The idea of natural selection basically follows the analyses of the heritable characters which passes from one generation into another, having the specific set of data or genome been transferred into there descendants. And how each specie goes through the process of survival in order to have more chances to acquire the required natural resources and shelter for them selves inside a region or area.
Chromosomal deletion is the loss of genetic code, caused by a segment of chromosome breaking away during DNA replication. The best answer is the third one, "when part of a chromosome breaks off and does not reattach."
