Why is dna with a high gc content more difficult to denature than that with a low gc content?

Due to the presence of three hydrogen bonds.

Explanation:

DNA or deoxyriboucleic acid is made up of polymers of nucleotide. The single nucleotide consists of a nitrogenous base, a pentose deoxyribose sugar and a phosphate group.

The nitrogenous bases are adenine, guanine, thymine and cytosine. Adenine is bonded with thymine with two hydrogen bonds whereas cytosine is bonded with guanine with three hydrogen bonds. Three hydrogen bonds are difficult to break as compared with two hydrogen bonds. Hence, DNA with more GC content is difficult to denature.

stress fractures occur largely in the feet and legs and are common in sports that require repetitive impact, primarily running/jumping sports such as gymnastics or track and field.