Enzymes only work with specific substrates because substrates:

each substrate has a unique 3-dimensional shape.

Explanation:

Enzymes are large and complex globular proteins that have one or more polypeptide chains. The part of the enzyme responsible for its action is the active center (site). The shape of the active center is very precisely adjusted to the substrate, similar to the key to the lock.

Due to the presence of the active site, the enzymes show a specificity property, which means that each enzyme acts on only one compound or group of similar compounds.

thermophiles, notice the prefix thermo.

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.