you answered yourself there buster.
DNA is bound together by covalent bonds between different molecules. It also contains proteins, which again are held together in their specific structures by covalent bonds.
Covalent bonds may be broken when high temperatures are applied. The temperatures that a food encounters during the cooking cause the DNA to be denatured, meaning it cannot be extracted. The same occurs with other proteins such as enzymes and antibodies.
Large trees and ferns need water to survive. This suggests that the biome was once very different from the desert it is today. #globalwarming lol
I would probably say d because Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. This leads to a reduction in fitness for both individuals, but the more fit individual survives and is able to reproduce.