400 micrograms a day of folic acid are recommended for all women of child-bearing age. Folic acid helps prevent neural tube defects in the first weeks of pregnancy, before most women even realize they are pregnant (and almost half of pregnancies in the U.S. are unintended). Knowing that folic acid promotes proper neural tube closure, which disease can be prevented by this supplement?

Question

A.  Spina bifida -- the vertebrae are unfused and may allow the spinal cord to protrude outside the body
B.  Horseshoe kidney -- the two kidneys are fused together across the midline
C.  Esophageal atresia -- the esophagous ends in a pouch, unconnected to the stomach
D.  Chronic otitis media -- frequent ear infections that can result from blocked eustachian tubes


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 neural tube? 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?

Answer 1

A.  Spina bifida -- the vertebrae are unfused and may allow the spinal cord to protrude outside the body

Clarify Question
What is the key concept addressed by the question?
     · This question is asking about the condition associated with incomplete closure of the neural tube.

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 the effects of the incomplete closure of the neural tube.


Gather Content
What do you already know about the neural tube? What other information is related to the question?
     · The dorsal ectoderm gives rise to the neural groove.
     · The neural tube has edges that fuse together early in a human pregnancy to form the neural tube.
     · The neural tube differentiates into the spinal cord and brain.
 
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
     · The kidney, Eustachian tubes, and esophagus are not derived from the ectoderm, so these answers can be disregarded.
     · The neural tube is derived from ectodermal tissue.
     · There is a relationship between adequate folic acid intake before and in early pregnancy and a decreased chance of spina bifida, which is the result of an incomplete closure of the neural tube.


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 formation of the neural tube in a new situation. If you got an incorrect answer, did you remember that the neural tube is derived from the ectoderm, or that if it does not close, the spinal cord may protrude through the vertebrae?