Once again, declan has failed to spike the ball over the net. his volleyball team is getting annoyed with him even though he is great during the rest of the game. which of the following skills should declan work on to improve his ability to spike the ball?
speed agility balance power

The skill that Declan should work on to improve his ability to spike the ball is the last option - power. Since he cannot get the ball over the net, it means that he isn't strong enough to do that, or rather his technique doesn't have enough strength. Thus, what he needs to work on is power. Speed and agility refer to the same thing, and balance won't help him here.