Final answer:
Chromosomes need to line up in the middle of the cell during mitosis to ensure equal distribution of chromosomes. In meiosis, chromosomes behave differently and undergo crossing-over to generate genetic variation.
Step-by-step explanation:
In mitosis, it is important for the chromosomes to line up in the middle of the cell during metaphase. This alignment ensures that each cell produced will receive an equal number of chromosomes. If the chromosomes did not align properly, it could result in an unequal distribution of chromosomes, leading to genetic abnormalities in the daughter cells.
In meiosis, the behavior of chromosomes is different compared to mitosis. During meiosis, homologous chromosomes line up in pairs during metaphase I. This allows for the exchange of genetic material between chromosomes, known as crossing-over. Additionally, meiosis produces daughter cells that have half the number of chromosomes as the original cell, allowing for genetic variation.