Final answer:
When examining a five-carbon sugar to determine if it is ribose or deoxyribose, one looks to see if there are two H on the 2'C carbon in the structure.
Step-by-step explanation:
The carbon atoms of the five-carbon sugar are numbered 1', 2', 3', 4', and 5'. When examining a five-carbon sugar to determine if it is ribose or deoxyribose, one looks to see if there are two H on the 2'C carbon in the structure.