CPP Resource Leveling and Resource Smoothing Discussion

I’m working on a management multi-part question and need the explanation and answer to help me learn.

What  are resource leveling and resource smoothing? Answer using your own  words but citing current scholarly research. What is the impact to the  critical path, and how is “float” used in leveling and smoothing  resources? Give an example of leveling and smoothing resources on a  project you know or can find through research.