Which best describes mitochondrial dna

Which element forms the basis of all organic organisms a carbon b oxygen c hydrogen d nitrogen

This is a biological reaction due to a stimulus. i need this quickly !

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit. there is a precise compatibility between the active site and the lactose molecule. specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed. reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.