What problem would result from disrupted development of the allantois in both birds and mammals?
A. Inability to retain the fluid that surrounds the embryo
B. Inability to form the placenta
C. Problems with gas exchange
D. Loss of nutritional stores
Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
Gather Content
What do you already know about the allantois? What other information is related to the question?
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
C. Problems with gas exchange
Clarify Question
What is the key concept addressed by the question?
· This question is addressing the function of the allantois.
What type of thinking is required?
· Apply level:
o You are being asked to take what you already know and use, or apply, it to determine the effects of the disrupted development of the allantois.
Gather Content
What do you already know about the allantois? What other information is related to the question?
· During development, the allantois of a bird embryo expands to form a sac that eventually fuses with the overlying chorion, just under the eggshell.
· The fusion of the allantois and chorion form a functioning unit, the chorioallantoic membrane, in which embryonic blood vessels, carried in the allantois, are brought close to the porous eggshell for gas exchange.
· The chorioallantoic membrane is thus the respiratory membrane of a bird embryo.
· The allantois in mammals contributes blood vessels to the structure that will become the umbilical cord, so that fetal blood can be delivered to the placenta for gas exchange.
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
· The allantois is not involved in retaining fluid around the embryo, so that answer can be disregarded.
· Maintaining nutritional stores or building the placenta are not functions of the allantois.
· Since the allantois is a respiratory membrane, if its development was disrupted, gas exchange would be impeded.
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
· Apply level:
o Answering this question correctly depended on your ability to use the nature of the allantois in a new situation. If you got an incorrect answer, did you remember that the allantois is a respirator membrane for bird embryos, or that it facilitates the development of the umbilical cord in mammals?
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