Thomas Edison had (a, an) idea which adjective belongs in the sentence

an

Explanation:

The word idea starts with a vowel and the adjective needed shouldn't also end with a vowel. And in this case, you can't use a because it's a vowel. So, you use an.

recent brain research has shown some surprising benefits as a result of formal musical training. learning to play a musical instrument appears to develop parts of the brain that can even influence academic results. the studies indicate that the earlier a child begins training, the more benefits there are. one such study showed that children who began musical studies before the age of seven had a more developed brain in the region where language production and auditory processing take place. scientists believe there is mounting evidence to show that early musical training can improve brain function.

explanation:

that his long years of service outweigh any faults he may have had.

he wanted to be remembered for the good things he did, one of those being when he gave up office so others would follow suit, but george washington wasn’t a man who thought he was perfect, he knew he made mistakes. he was a very talented soldier with a natural gift of tactic.