Self-study
North American eastern white cedars grow both on cliff faces and in forests. ██████ ███████ ██ ███████ █████ █████ ███████ ████ ███ ██████████ ███ ██████ ████ ██████ ████ █████████ ███ ██████ ██ ██████ ███████ ██ ████████ █████ ████ ███████ ████ ████████ ███ ████ █████ ███ ███ ███████ █████ ██████ █████ ██ ███████ ███ ██ ███ ██ ████ ███████ ██████ █████ ████ ██ █████ █████ ███ ████ ████ ████ ███████ █████ ████
"Surprising" Phenomenon
Why do many cedars on cliff faces, which are relatively undernourished, live longer than cedars in forests?
Objective
A hypothesis explaining this discrepancy must state a key difference between cedars on cliff faces and cedars in forests. This difference must result in many cedars on cliff faces living longer than most cedars in forests.
1.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ██████████ ██ ███ ████ ██ ███ ██████ ██ █████ █████ ███ █████ ██ ████████
a
The conditions on █████ █████ ███ ███████ ██ █████ ██ ████ █████ ██████ █████ █████ ███ ███ ████ ██████
This does not explain the relative longevity of cedars on cliff faces. It suggests that environmental conditions cause cedars on cliff faces to grow shorter, but states no relationship between a cedar's height and its life span.
b
In areas where ███████ █████ ██████ █████ ██████ █████ ███ ██████████ █████████ ███ █████ ██████ █████ █████ ██████
This explains why cedars on cliff faces more often live to old age. Forest fires kill many cedars in forests, but do not reach cedars on cliff faces, so cedars in forests are exposed to a survival risk that cedars on cliff faces are not.
c
Trees that are █████ ████ █ ███ ███████ █████ █████ ██ ████ ███ ██████████ █████ █████ ██ █████ █████
This is not a difference between cedars in forests and cedars on cliff faces. If all cedars lose their bark’s outer layer in old age, then cedars in both places should be equally affected.
d
The roots of ██████ ██ █████ █████ █████ ██ ██████ ██ ███ ██████ ███ ████ ███ █████ ███ ██ █████ ████ ████ ████ █ ██████ ███ ████ ██ ██████ ██ ████ ███ ███████
This explains why cedars on cliff faces are shorter, but not why more of them grow old. It states no relationship between the height of a tree and its longevity.
e
Eastern white cedar ████ ██ ███ ████ ██ ██ ████ ███ ████████ ██ ██████ ██████████ ███ ██ ██ ████████████ ████ ██ ████ ██████████
This rules out a possible explanation, rather than provide one. It implies that cedars are only infrequently harvested for wood, casting doubt on the possibility that cedars in forests are killed in large numbers by humans.