In vertebrates with a double-loop circulation as illustrated in figure 27–4, the loop that passes through the lungs is responsible for:

a. exchanging carbon dioxide for oxygen from the air.
b. exchanging oxygen for carbon dioxide from the air.
c. delivering oxygen-rich blood to the body.
d. delivering oxygen-poor blood to the heart.

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

The earths core is made up mainly of what 2 substances? 2. like an egg, earth has a core, a layer surrounding the core, and a thin, hard outer layer. which layers of the earth match the layers of an egg?

Kara has a plant that produces either purple or white flowers. she crosses a plant that has two recessive alleles for white flowers with a plant that has two dominant alleles for purple flowers. which result would be true of all of the offspring? a) all of the offspring would have two recessive alleles and white flowers. b) all of the offspring would have two dominant alleles and purple flowers. c) all of the offspring would have one recessive allele, one dominant allele, and white flowers. d) all of the offspring would have one recessive allele, one dominant allele, and purple flowers