Answer:
B) ATP has three phosphates; ADP has two.
Step-by-step explanation:
ATP and ADP are composed of three components known as adenine base, ribose sugar and phosphate groups. ATP is a high energy molecule which has three phosphate groups attached to a ribose sugar. ADP is a somewhat similar molecule composed of the same adenine and ribose sugar with only two phosphate molecules. The key difference between ATP and ADP is the number of phosphate groups they contain.