Self-study
Mature white pines intercept almost all the sunlight that shines on them. ████ █████ █ ████ ██████ ████ █████ ████████ ███ ████ ████ ██ ██████████ ██████ ██ █████ ████ ████ █████ ███ █████ ████ ██ █ █████ ██ ████ ██████ ██████ █████ ███████ ███ ██████ ██████ ███ ████ ██████ █████ █████ ██████ ██████████ ██ █████ ███ ██████ █████ ████ ██ █ █████ ██████ █ █████ ██ █████ ████████ ██ ███████ ███ ██████ █████ ██████ ██ ██ █ ████ ███ ████ ████████
Summary
Mature white pines intercept almost all the sunlight they receive. They leave a deep litter and grow tall enough so that little light reaches the forest floor even with little gaps between trees. White pines cannot regenerate in their own shade.
Strongly Supported Conclusions
In a forest of mature white pines, it is unlikely that any adjacent pines differ widely in age.
13.
Which one of the following ████ █████████ █████████ ███ █████████
a
the ages of ███ █████ ██ ███ █████ ██ ███ ██████ ████ ████ █████ ██ ████ ████ ████ ███ ██████ ██ ████ ██ █████ █ █████ ████ ██ ████ ██ ████████
This is strongly supported because we know that mature white pines next to each other leave so little sunlight on the forest floor that white pines cannot regenerate. This would prevent young trees from emerging where pines are already mature.
b
the land on █████ ███ █████ ██ ███ ███████ ███ ████ ███████ ██ ███ █████ ██ ███ ████ ████ ███ █████ ██ ███ █████ █████ ███████ ███████
This is unsupported because it is not required that all white pines are cleared for new ones to grow. The stimulus only tells us that stands of mature white pines prevent regeneration.
c
competition among the █████ ██ ███ █████ ███ ████████ ████ ████ ██████ ██ ████ ██████ █████ ███ ███ █████ ████ ████████ ███████
This is unsupported because even though the competition for sunlight may prevent new white pines from growing between mature trees, we have no reason to suspect that already mature trees will compete with each other for sunlight.
d
other species of █████ ████ ████ █████ ██ ████████ ███ ██████ ██████████ █████████ ███ ██ ███ █████ █████
This is unsupported because the stimulus provides no information on other trees outcompeting stands of mature white pines.
e
any differences in ███ ███████ ██ ███ █████ ██ ███ █████ ███ ████████████ ██████ ██ ███████████ ██ ███ ████ ██ ███ █████
This is unsupported because we don’t know that there aren’t other factors like rain or nutrition that contribute to height differences.