Answer: Electrophoresis combs are used to create the wells in gels for electrophoresis, a technique that uses the electrical of molecules to separate them by their length. It often used to analyze DNA fragments. When a gel is poured a comb is inserted.
The reason that the answer is 1/4 is because the young man, his grandfather, his father, and his mother equal 4 people. The young man is 1 person. 1 person/4 people = 1/4.
