A Geneticist Is Conducting Research on Pest-Resistant Walnut Trees

Multiple Choice

A geneticist is conducting research on pest-resistant walnut trees. He has developed a set of trees, when crossed, to produce offspring as follows: 50% of all trees are very resistant, 30% of trees are somewhat resistant, and 20% are susceptible to invasion by pest. The probability model for the experiment of crossing two trees from the set of trees is:

A) P(susceptible) = 0.2, P(resistant) = 0.8.
B) P(very resistant) = 0.5, P(somewhat resistant) = 0.3, P(susceptible) =0.2.
C) P(very resistant) = 0.5, P(not very resistant) = 0.5.
D) P(susceptible) = 0.2, P(not susceptible) = 0.8.