Self-study
Two paleontologists, Dr. █████ ███ ███ █████ ████████ ████ ███ ██████████████ ██ ███████ ██████████ ████ ████ ████ █████ █████ ██████████ ██ ████████ ████████ ███ ██ ████ ██ ███ █████ ██████ ████ ███ ███████ █████ ███████ ██████████ █████ ████ ████ █████ ████████████████ █ ████████ ████ ███ █ ███ ███ ███████████ ████████ ██ ███ ████ ████ ████████ █████ ███ ██████████ ████████ ████ ██ ████████ ████ █████ ██████ ████ █████ ████ ███ ██ ████ ██ ██ ██████████ ██████████████ ███████ ██ ███████ ███ ████ ████ ██ ███ █████ ██ ███ █████ █████ ███ ████ ███████ ███ █████████ ███████████
Dr. Tyson's Argument
Dr. Tyson concludes that certain footprints were made by a hominid. Dr. Tyson's support for this is the shape of the footprints, which have a somewhat square heel and a big toe right next to the next toe. These are human-like footprint characteristics.
Dr. Rees' Argument
Dr. Rees concludes that the footprints were not made by a hominid. Dr. Rees' support is that if a hominid made the footprints, then that hominid must have walked with a strange cross-stepping gait. This gait would have necessitated stepping with the left foot to the right of the right foot, and so on.
Disagreement
Drs. Tyson and Rees are examining the same footprints, but come to different conclusions about whether the footprints were made by a hominid. In coming to these conclusions, the two paleontologists examine different characteristics of the footprints: Dr. Tyson focuses on the shape of the footprints, whereas Dr. Rees focuses on how the footprints are placed relative to each other. Neither paleontologist denies the evidence of the other; they just disagree about what evidence is most important.
8.
Which one of the following, ██ █████ ████ █████████ ██████████ ███ █████████ ███████████
a
The footprints showing █████ ███████████████ ████ ███████ █████ ██ ██ █████ ███ ████████ ████████████
(A) leaves Dr. Tyson's argument in the same place as before. Whether the footprints were made by one or more individuals, they still have the same characteristics, and we have no more reason to believe something else was responsible.
b
Certain species of █████ ███ ████ ████ ████ █████ █████ ██████ ████ ███ ███████ ███ ██ ████ ████ ███ ███ ███████ ███ ███ ███ █████████ ███ ███ ███ ████████ ████
(B) gives us an alternative explanation for what kind of animal might have left these footprints. These bears would account for the same characteristics that Dr. Tyson focuses on: a square heel and a big toe next to a smaller toe. However, the placement of that big toe would also explain the apparent cross-stepping, making bears a better fit for the evidence.
c
Footprints shaped like █ █████████ ████ ██ ███ ████ █ ██████████████ ███████ █████ ██ ████ ██ █████ ██ █ ████ ████ ████ ████ ██ ███ ███ ███ ████ ██ ██████████ ███ ████████████████
(C) doesn't tell us anything useful—it doesn't narrow down or change the possibilities to explain the site G footprints. We don't know if the same species left both sets of footprints, or even what species left the site M footprints. So we're left in the same place as before.
d
When the moist ████████ ███ ██████ ██████ █████ ██████████ ██████ ██ ███ ██████ ██████████ ████ ███████ ██ ████ ██ ███ ██████████ ████ ███████
What details were erased, and how important were they? (D) doesn't tell us, so it doesn't provide any new useful directions. If there was some key characteristic erased that indicated a non-hominid, that would be useful. But we can't assume that's the case.
e
Most of the █████ ██████████ ██ ████ █ ████ ██ ███████ ████ ███████
We know the footprints in question weren't hooves, though, so (E) doesn't help us. We can't make any assumptions about whether or not hominids co-existed with hooved species. And without that information, (E) can't weaken.