I believe the answer is B. Because it didn't rain very often
20,000 soldiers fought in the french and Indian war.
They break down dead plants and animals, as well as they break down waste, I'm not 100% sure if this is answer you're looking for if not I'm sorry.
Roediger and Mcdermott performed an experiment with over 60 test subjects that were exposed in different stimuli. In their experiment they concluded that there must have been a trade-off of between the false memory susceptibility and categorization ability and that the superior performance on one will relate to having superior performance to the other.
Without a lot of knowledge about black communities in the 1920's, I'd have to say it be the creation of a song genre, jazz.