I would say DNA needs to be in a double helix so it can be unraveled and duplicated during cell mitosis
A well mixed serial dilution is critical to achieving a homogenous mixture that has a constant concentration over the sample volume. If the dilution is not well mixed then it will affect the subsequent dilutions consent ration which will lead to percent error
I’ll give you some key points and after that you should be fine, tide, swept underneath and over, density differences and climate change