"The difference between these types of dry yeast is simple: active dry yeast has a larger granule and needs to be dissolved in water before using, while instant yeast has a more fine texture and can be mixed right into dry ingredients."
Includes a pretty interesting discussion of dealing with overdispersion in mixed-effects models (e.g., count models) by using individual-level fixed effects. It also includes a whole series of citations.
MYTH: The steps will flatten out and all the people will slide down. TRUTH: This is impossible. Each step is a full triangular structure consisting of tread and riser supported on a track and cannot flatten out.