Meiosis is a process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell. Meiosis usually involves two distinct divisions called meiosis I and meiosis II. By the end of meiosis, a single diploid cell has produced four haploid cells. After interphase I, the cell begins to divide, and the chromosomes pair up. In prophase 1 of meiosis, each replicated chromosome pairs with its corresponding homologous chromosome. This pairing forms a structure called a tetrad, which contains four chromatids. As the chromosomes pair, they sometimes undergo a process called crossing-over.

Which is a true statement of crossing-over?

A. Homologous chromosomes move to opposite ends of dividing cells

B. During crossing-over, bits and pieces of the homologous chromosomes are exchanged

C. The DNA of the diploid cell is copied

D. Crossing over decreases genetic diversity