Can you me with this question .

dna is made of two chains of nucleotides. which type of bonds hold the chains together?
a= hydrogen bonds
b= covalent bonds
c= ionic bonds
d= polar covalent bonds

Aboy with an extra x chromosome probably has which of the following syndromes?

What is one energy transformation that is taking place in the photo? radiant energy to thermal energy thermal energy to nuclear energy chemical energy to thermal energy radiant energy to chemical energy

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.