A pea plant must have exactly one of each of the following pairs of traits: short (s) or tall (t); round (r) or wrinkled (w) seeds; yellow (y) or green (g) peas; and white (wh) or purple (p) flowers (for example, short, wrinkled, green pea with white flowers).

(a) How many different classifications of pea plants are possible? 

(b) Use a tree diagram to determine all the classifications possible.  If each characteristic is equally likely 

(c) determine the probability that the pea plant will have round peas.

(d) determine the probability that the pea plant will be short, have wrinkled seeds, have yellow seeds, and have purple flowers.

Use the counting principle to determine the answer to part (a). Assume that each event is equally likely to occur.