Caffeine improves mental alertness and motor coordination. A university research study was conducted to examine how caffeine affects fine motor skills. Ten teen girls, ages 14 to 18, were given 200 mg of caffeine per day for 30 days. Thirty minutes after taking the caffeine, each subject took a timed fine motor skills test in which they fitted 20 small beads onto pegs. The graph compares each subject’s average results on the same test done 30 minutes before and after taking the caffeine. Which group would most benefit from the claim?

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.