What type of conjunction away come in pairs

 They get their name from the fact that they work together (co-) and relate one sentence element to another. Correlative conjunctions include pairs like “both/and,” “whether/or,” “either/or,” “neither/nor,” “not/but” and “not only/but also."  they need to be in pairs always 

wood chucks can't chuck wood so no wood

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: