Which of the following is a correct statement about an organism and its environment?
a. the gastrovascular cavity provides the nutrient exchange surface in mammals.
b. an animal is a closed system that is separate and distinct from its environment.
c. interstitial fluid is the go-between for body cells and the circulatory system.
d. animals are able to live as long as they remain isolated from their environments. e. none of the choices is correct.

20 the compound al(nh3)2 has atoms of nitrogen.

In a population that is in hardy-weinberg equilibrium, there are two possible alleles for a certain gene, a and a. if the frequency of allele a is 0.4, what fraction of the population is heterozygous? a. 0.40 b. 0.60 c. 0.16 d. 0.48

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