The prefix auto- means “self.” The root word troph comes from a Greek word that means “to feed.” How could knowledge of these word parts help you define the word autotroph?

autotroph would mean to self feed or you are are capable of feeding yourself

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.