In this hands-on, minds-on activity, students use model chromosomes and answer analysis and discussion questions to learn about the processes of meiosis and fertilization. As they model meiosis and fertilization, students follow the alleles of a human gene from the parents' body cells through gametes to zygotes; thus, students learn how a person inherits one copy of each gene from each of his/her parents. To learn how meiosis contributes to genetic variation, students analyze the results of cros