I need help with this questionWatch
What are the advantages of having hydrogen bonds in the centre?
The whole reason Adenine binds to Thymine and Cytosine binds to Guanine is because this maximises the number of hydrogen bonds you can form.Hydrogen bonding thus allows the formation of specific base pairs.You would not get that with the other kinds of bonding.
Also,Hydrogen bonds are weak but because DNA is a long molecule,you have lots of hydrogen bonds,the sum of which helps keep the DNA molecule together.
Hydrogen bonds being weak is important since they can still be broken easily when you need to replicate DNA.If you had strong covalent bonds instead,unwinding the dna double helix would be energetically costly.