Which statement best describes the function of the respiratory passageways of a human?
A) They permit digestive end-products to make
contact with body cells.
B) They permit exchange between the external
atmosphere and the circulatory system.
C) They transport gaseous cellular wastes from
body cells to the lungs for excretion.
D) They regulate the amount of ammonia and salt
dissolved in body fluids.

Suppose a particular species of tulip plant has three alleles for the gene that codes for flower color. the cr allele produces red tulips, the cp allele produces purple tulips, and the cw allele produces white tulips. cr is dominant over cp and cw, and cp is dominant over cw. for each of the following crosses, determine the expected ratio of offspring for each flower color. cr cp x cp cw cr cw x cp cw 1 red: 1 purple : 0 white, 1 red: 2 purple: 1 white, 2 red: 1 purple 1 white, 1 red: 3 purple : 0 white, 2 red: 0 purple : 2 white, 2 red: 2 purple : 0 white