Deafness may be caused by malformation of the stapes bone. This may occur by...
A. failure of Meckel's Cartilage to degenerate properly.
B. failure of paraxial mesoderm and neural crest cells to merge properly and form the stapes.
C. failure of Reichert's Cartilage to degenerate properly.
D. failure of the stapes to arise from the incus.
E. failure of the stapes to arise from the tympanic membrane.
Answer: B. failure of paraxial mesoderm and neural crest cells to merge properly and form the stapes.
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Describe the breeding program initiated by King Frederick William of Prussia in the early 1700s to supply tall soldiers to the Potsdam Grenadier Guard. Was it successful? Why or why not?
What will be an ideal response?
Which characteristics best describe earthworms?
a. polychaete; fluid filled coelom b. oligochaete; open circulatory system c. moves by only longitudinal muscle contraction and hydrostatic skeleton d. oligochaete; scavengers; closed circulatory system e. hermaphrodites that fertilize themselves; closed circulatory system
Tetralogy of Fallot (TF) is a genetic disorder characterized by four major malformations of the heart. The circulation of blood is abnormal, so TF patients have too little oxygen in their blood. Inadequate oxygen levels result in damaged mitochondrial membranes, which in turn cause cells to self-destruct. In 2004, Sarah Kuruvilla and her colleagues looked at abnormalities in the mitochondria of
heart muscle in TF patients. Some of their results are shown in Figure 7.13 (on previous slide). What conclusion do the data support about mitochondrial abnormalities and levels of oxygen saturation of the blood (SPO2)?
1.Abnormalities in size of mitochondria is not an important factor.
2.Abnormalities in number of mitochondria have a significant impact on SPO2.
3.The combination of broken mitochondria and abnormal numbers of mitochondria causes the lowest levels of SPO2.
4.Younger patients have lower levels of SPO2.
In one strand of a DNA molecule, adjacent nucleotides are joined by a(n) phosphodiester linkage
__________________ Indicate whether the statement is true or false.