What are compressed yeas, Dry Active yeast, and quick rise dry yeast?

Yeast, as you are thinking of it in this questions, is the
rising agent used in baking breads and other baked goods. The process involves mixing
the yeast with some sort of sugar; the mixture gives off carbon dioxide bubbles which
cause the dough to rise. Moisture of some sort is also required for the fermentation and
rising process to take place.

Compressed yeast can also be
called cake yeast. It is yeast that still has some moisture in it when it is packaged
for sale. It is perishable and must be used by the given deadline for best
results.

Dry active yeast is a dry, granular ingredient.
Active yeast cells are covered by dried cells and need to be rehydrated before becoming
active and able to cause dough to rise.

Quick rise dry
yeast, or rapid-rise yeast, has smaller pieces than dry active yeast. This means it is
able to dissolve and begin fermenting more quickly. Bread machines make use of quick
rise dry yeast due to the short, inflexible time settings
involved.