What is compound interest?
a. interest that is accumulated over a period of time but only occurs in a passbook savings account
b. when you earn interest on the interest you have already made
c. when you earn interest on only the principal
d. when you earn interest on the difference between the principal and the interest

the answer is D

Explanation:

Compound interest is the addition of interest to the principal sum of a loan or deposit, or in other words, interest on interest.

the president was the speaker and it was a great part of history.

explanation:

video of the national aeronautic space administration's (nasa) coverage of president john f. kennedy’s address at rice university, houston, texas, concerning the nation's efforts in space exploration. in his speech the president discusses the necessity for the united states to become an international leader in space exploration and famously states, "we choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."