1.Why did you use a pencil to mark the paper and not a pen? 2.Why do you have to use a different capillary tube for each sample? 3.Why is it very important in the amino acid chromatogram not to touch the paper with your fingers or hands? 4.If two samples have identical Rf values does this mean that they are necessarily identical molecules? Explain 5.What is your unknown? How do you know?

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.