22. Describe the four main characteristics of an ani- mal's respiratory surface.

23. Trace the pathway of air through the human res-
piratory system, from the nostrils to the lungs. At
what point within the lungs do the oxygen mol-
ecules really enter the body?

92 sathe best for the question 11. most animals and plants reproduce sexually. this means that dna is passed down to new organisms from two parental organisms. which of the following is a key advantage of sexual reproduction?

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels

Nhumans, abo blood types refer to glycoproteins in the membranes of red blood cells. there are three alleles for this autosomal gene: ia, ib, and i. the ia allele codes for the a glycoprotein, the ib allele codes for the b glycoprotein, and the i allele doesn't code for any membrane glycoprotein. ia and ib are codominant, and i is recessive to both ia and ib. people with type a blood have the genotypes iaia or iai, people with type b blood are ibib or ibi, people with type ab blood are iaib, and people with type o blood are ii. if a woman with type ab blood marries a man with type o blood, which of the following blood types could their children possibly have? in humans, abo blood types refer to glycoproteins in the membranes of red blood cells. there are three alleles for this autosomal gene: ia, ib, and i. the ia allele codes for the a glycoprotein, the ib allele codes for the b glycoprotein, and the i allele doesn't code for any membrane glycoprotein. ia and ib are codominant, and i is recessive to both ia and ib. people with type a blood have the genotypes iaia or iai, people with type b blood are ibib or ibi, people with type ab blood are iaib, and people with type o blood are ii. if a woman with type ab blood marries a man with type o blood, which of the following blood types could their children possibly have? a, b, ab, and o ab and o a, b, and o a and b