Which of the following will shift the oxygen dissociation curve to the left?

The methanol in Wright stain:

a. Establishes the alkaline pH need for staining b. Fixes the cells c. Establishes the acid pH needed for staining d. Serves no function except as a solvent for the dyes

_______, the natural replacement of feathers, occurs in birds once or twice per year

Fill in the blank(s) with correct word