In the video the presenter uses a pair of scissors as an analogy for an enzyme. identify the active site of the scissors enzyme ,it's substrate, and the chemical reaction that catalyzes

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

a. by using fur or clothes to trap heat energy near the body

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.