What do veins have that arteries lack?
a. a tunica externa
b. oxygenated blood
c. an inner membrane of endothelium
d. blood flowing from the heart
e. valves
E
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Imagine a red blood cell leaving the right ventricle of your heart. To which chamber of the heart will that cell return first?
A. right atrium B. right ventricle C. left atrium D. left ventricle E. impossible to say from information given
The membrane that surrounds the central vacuole is the ____
a. chloroplast b. tonoplast c. chromoplast d. amyloplast e. ionoplast
61. Tiktaalik either crawled or paddled in shallow tropical streams about 380 MYA, during the late Devonian period. These shallow waters often became anaerobic. What selective advantage would Tiktaalik have under these conditions?
A. It could crawl on shore and feed on birds and reptiles that were on land. B. It could lift its head out of the water and breathe air through its gills. C. It could crawl out of the water and walk over to new shallow streams. D. It could lift its head out of the water and breathe air through its lungs. E. It could swim better than fish.
In animals, the egg and sperm cells are:
A. polyploid. B. diploid. C. haploid. D. None of these choices are correct.