Caffeine is a stimulant to the central nervous system. regular consumption may cause physical dependence; would it be appropriate to consider caffeine an addictive substance?

Yes, because most people can't start their day without coffee which has caffeine in it.

your a sped   no one cares

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.