Jamie grinds his teeth at night, so his dentist suggested wearing a mouth guard. after wearing the mouth guard for two weeks jamie noticed that his jaw no longer hurt during the day. about two weeks later, jaime’s parents received a call from the dentist’s billing department, who indicated that their insurance did not cover the cost of the mouth guard. a effect is that jaime’s jaw no longer hurts during the day. a effect is that his parents’ health insurance did not cover the cost of the mouth guard.
a.+; -
b.-; +

d.+,+