The popular notion that a tree's age can be determined by counting the number of internal rings in its trunk is generally true. However, to help regulate the internal temperature of the tree, the outermost layers of wood of the Brazilian ash often peel away when the temperature exceeds 95 degrees Fahrenheit, leaving the tree with fewer rings than it would otherwise have. So only if the temperature in the Brazilian ash's environment never exceeds 95 degrees Fahrenheit will its rings be a reliable measure of the tree's age.
Which of the following is an assumption on which the argument above depends?
A) The growth of new rings in a tree is not a function of levels of precipitation.
B) Only the Brazilian ash loses rings because of excessive heat.
C) Only one day of temperatures above 95 degrees Fahrenheit is needed to cause the Brazilian ash to lose a ring.
D) The internal rings of all trees are of uniform thickness.
E) The number of rings that will be lost when the temperature exceeds 95 degrees Fahrenheit is not predictable.
The OA is E, but what's wrong with C
The MGMAT explanation says that the number of days it takes for the tree to lose a ring in excessive heat is irrelevant. But why wouldn't it be relevant? If it only takes one day to lose a ring, then the author's conclusion, "only if the temperature in the Brazilian ash's environment never exceeds 95 degrees Fahrenheit will its rings be a reliable measure of the tree's age," would be true. If C had said, "it takes 2 days for the tree to lose a ring," the author's conclusion would be questionable, since one day above 95 degrees would not cause the tree to lose a ring. Therefore, saying that it takes "1 day to lose a ring" is a relevant assumption, right?
Which of the following is an assumption on which the argument above depends?
A) The growth of new rings in a tree is not a function of levels of precipitation.
B) Only the Brazilian ash loses rings because of excessive heat.
C) Only one day of temperatures above 95 degrees Fahrenheit is needed to cause the Brazilian ash to lose a ring.
D) The internal rings of all trees are of uniform thickness.
E) The number of rings that will be lost when the temperature exceeds 95 degrees Fahrenheit is not predictable.
The OA is E, but what's wrong with C
The MGMAT explanation says that the number of days it takes for the tree to lose a ring in excessive heat is irrelevant. But why wouldn't it be relevant? If it only takes one day to lose a ring, then the author's conclusion, "only if the temperature in the Brazilian ash's environment never exceeds 95 degrees Fahrenheit will its rings be a reliable measure of the tree's age," would be true. If C had said, "it takes 2 days for the tree to lose a ring," the author's conclusion would be questionable, since one day above 95 degrees would not cause the tree to lose a ring. Therefore, saying that it takes "1 day to lose a ring" is a relevant assumption, right?
