I've heard two sides to this story all over the net:

1. A muscle is a muscle is a muscle: Every muscle needs stress and the same amount of rest to grow.

2. Work your abs every day: They don't require as long to rest as your other muscles.

So I have a few questions for you all:

A) Are core muscles truly this resilient? Do they need less rest (can you work them out moderately everyday) or do they need just as much rest as any other muscle you work on?

B) Is the two-days rest between working out muscle groups a good rule of thumb, or is this somewhat unique to the individual?

C) Is rest necessary for body-weight exercises, like pushups, pullups, etc. or is this mainly for lifting heavy weight in the gym?

Not sure if this could have been split between a few posts, but I'm sure you guys can handle it! Thanks!