a) hunter gatherers who built mounds
The various cultures collectively termed "Mound Builders" were inhabitants of North America who, during a circa 5,000-year period, constructed various styles of earthen mounds for religious, ceremonial, burial, and elite residential purposes.
Destroyed idols in Kaaba, rededicated Kaaba to Allah
Answer:
In this order:
B, A, D, C, E
I'm unsure about the Preparedness Movement as I only know that it picked up in April.
It was groundbreaking because it was funny and educational and approached modern topics in a way that was accessible to children, yet it wasn't offending anyone. It was one of the first show whose educational effects on children were studied and it is considered to be a very positive show and a good thing to watch. The long term impact is that it created a legacy of a hundred million people watching the show in their lifetime, usually when children.