Question

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.

Answer 1

The argument assumes that the loss of internal rings of the Brazilian ash when the temperature exceeds 95 degrees Fahrenheit is unpredictable, undermining the reliability of this method for age determination. The correct option is E The number of rings that will be lost when the temperature exceeds 95 degrees Fahrenheit is not predictable.

Step-by-step explanation:

The assumption on which the argument depends is that the number of rings that will be lost when the temperature exceeds 95 degrees Fahrenheit is not predictable (Option E).

This is because the conclusion only holds if there is a reliable way to determine whether the temperature has exceeded 95 degrees Fahrenheit without affecting the count of internal rings.

Since rings are indicators of a year's growth cycle, with earlywood and latewood, being able to count them accurately is essential for determining the age of the tree. Unpredictable loss of rings due to temperature would make this method unreliable.

The assumption on which the argument depends is that the number of rings that will be lost when the temperature exceeds 95 degrees Fahrenheit is not predictable. This means that the peeling away of the outermost layers of wood in the Brazilian ash's trunk cannot be determined or controlled, and it may vary from tree to tree or under different environmental conditions.

The correct option is E The number of rings that will be lost when the temperature exceeds 95 degrees Fahrenheit is not predictable.