AP BIOLOGY

Detailed explanation-1: -Chromosomes in the original cell are duplicated to ensure that the two new cells have full copies of the necessary genetic information. The process of mitosis generates new cells that are genetically identical to each other. Mitosis helps organisms grow in size and repair damaged tissue.

Detailed explanation-2: -Crossing over does not occur in mitosis. Crossing over occurs in telophase right before the cells split since all the DNA and cell growth has occurred by this point. Crossing over occurs in anaphase at each pole of the cell where the chromosomes are packed together.

Detailed explanation-3: -Mitosis occurs during development, creating more cells that allow an organism to grow, but it also takes place throughout the lifetime of an organism, as means to replace old cells with new ones.

Detailed explanation-4: -In general, epithelial cells have a far higher turnover and cancer incidence than other types of cells, accounting for 80% of all human cancers. For example, for cells in the jejunum, the average age of all cells has been calculated at   10.7 years.