I’m not entirely sure about what you’re asking but chargaff’s rule is the thing that states that the amount of each “letter” in DNA is equal to its pair. Guanine (g) pairs with cytosine (C) and the same with adenine(A) and thymine (T). I’m sorry my answer is so vague, but I hope it helps a little!
1.A taste bud
2. They are dound on the top part of the tongue
It is important in determining whether injuries/death was an accident or purposeful, and if purposeful, who, how and why did someone do it. They determine the weapon through the ligature marks left, the shape, force and impact of the injury, the location of the injury, and by analysing any fragments and trace evidence left on the wound
If DNA is found at a crime scene it can help locate people that were at the crime scene. If the criminal has committed crimes before their DNA will already be in the police system. If not they can take samples from suspects and pinpoint who committed the crime.