Viroids and prions differ in that viroids are believed to contain only
______, while prions are believed to contain only _______.
a. carbohydrate; amino acids
b. nucleic acid; protein
c. amino acids; carbohydrate
d. protein; nucleic acid
______, while prions are believed to contain only _______.
a. carbohydrate; amino acids
b. nucleic acid; protein
c. amino acids; carbohydrate
d. protein; nucleic acid