Why is the phloem in a leaf important to the roots of a plant?
A. It transports oxygen to the roots of the plant.
O B. It transports blastocysts to the roots of the plant.
O C. It transports water from the roots to the leaves.
OD. It transports carbohydrates to the roots.

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.