There are so many examples for that in different areas, like biology experiment carried out in our lab recently.
Here's one link:https://www.creative-biogene.com/support/Knockout-Cell-Lines-in-Antibody-Screening-and-Validation.html
A) a common ancestor
Homologous structures are structures that are similar in related organisms. There is a basic pattern of bones which can be inherited from a common ancestor
Hair follicles is the hair coming out of the subcutaneous layer
The answer is B. Meiosis involves two cycle of cell division.
