How does radiation differ from convection? a. radiation can move through empty space to transfer heat; convection cannot. b. radiation needs a medium in order for heat to transfer; convection does not. c. radiation requires objects to have direct physical contact; convection does not. d. radiation transmits heat by circulating particles in an object; convection does not.

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.