The extract of a plant native to Taiwan has been tested as a possible treatment for Leukemia. One of the chemical compounds produced from the plant was analyzed for a particular collagen. The collagen amount was found to be normally distributed with a mean of 71 and standard deviation of 10 grams per mililiter (g/mm). Suppose that a plant is randomly selected and the collegan amount is measured.

a) What is the probability that the amount is greater than 68 g/mm?

b) What is the probability that the amount is less than 79 g/mm?

c) What percentage plants have a collegan amount within 1 standard deviations of the mean?