Passage I
The mitotic index (MI) for a group of cells is calculated as follows:
MI = 
Figure 1 shows the average MI for onion root tip cells as a function of their distance from the root cap.
Five hundred mitotic onion root tip cells were examined. Figure 2 shows the number of cells in each of the 4 mitotic phases.
Figure 3 shows 4 onion root tip cells (Cells 1-4), each of. which is in 1 of the 4 mitotic phases. In Figure 3, each phase is shown once. However, the cells are not arranged in order of the phases of mitosis.
Figure 3 adapted from Peter H. Raven, Ray F. Evert, and Susan E. Eichhorn, Biology of Plants, 4th ed. @1986 by Worth Publishers, Inc.
2. Based on Figure 1, of the onion root tip cells that are 2.2 mm from the root cap, the percent that are in mitosis most likely falls within which of the following ranges?
Your Answer is
Correct Answer is F
Explanation
Put value questions. Look at figure 1, judging from the trend of several points, when the abscissa is 2.2mm, the ordinate should be less than or equal to 0.01, that is, 1.0%