If the base pairs in a DNA strand were held together with covalent bonds instead of hydrogen bonds, how would cells have to operate differently? New DNA would need to be made each time the strand was opened.
The cell would have to take in and use more energy in order to break the covalent bonds.
Each time the DNA strand opened the cell would need to replace the nitrogenous bases.
The cell could only open and close the DNA strand when it replicated.

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.