Nad and fad work by loading and unloading and during energy transfers.

Hydrogen and electrons

Explanation:

Nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD) serve as reducing power during energy transfers. One NAD+ accepts one hydrogen ions and two electrons and becomes reduced into NADH. Likewise, FAD accepts two hydrogen ions and two electrons and is reduced into FADH2. Oxidation of NADH and FADH2 into NAD+ and FAD respectively releases both hydrogen ions and electrons.  

For example, some of the energy of glucose released during glycolysis and Kreb's cycle is temporarily stored in the form of NADH and FADH2. Oxidation of NADH and FADH2 via electron transfer chain of mitochondria releases both electrons and hydrogen ions (protons). The protons are pumped across the inner mitochondrial membrane to generate the proton concentration gradient.  

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.

b. to discover aspects of the natural world.

hopefully i .