Try reading the book, I know that will have ALL of the answers you will need to be successful.
Answer:
The correct answer is:
It's necessary to collect DNA from male siblings, fathers, or paternal grandfathers
Explanation:
This happens because a parent gives half their DNA to their child. This means that when 10 STRs are studied, at least 10 bands will be identical on a gel comparing one parent and child. The Y chromosomal DNA is passed on from father to son, so it represents a nearly unbroken chain that moves through all recorded history.
