Which of the following statements is true?
a. Crossing over occurs during prophase II of meiosis.
b. Linked genes are found on different chromosomes.
c. All of the traits that Mendel studied?seed color, pod shape, flower color, and others?are due to genes linked on the same chromosome.
d. The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%.
e. The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.