noboru wrote:
Two paleontologists, Dr Tyson and Dr. Rees, disagree over the interpretation of certain footprints that were left among other footprints in hardened volcanic ash at site G. Dr. Tyson claims they are clearly early hominid footprints since they show human characteristics: a squarish heel and a big toe immediately adjacent to the next toe. However, since the footprints indicate that if hominids made those prints they would have had to walk in an unexpected cross-stepping manner, by placing the left foot to the right of the right foot. Dr. Rees rejects Dr. Tyson’s conclusion.
Which one of the following, if true, most seriously undermines Dr. Tyson’s conclusion?
(A) The foot prints showing human characteristics were clearly those of at least two distinct individuals.
(B) Certain species of bears had feet very like human feet, except that the outside toe on each foot was the biggest toe and the innermost toe was the smallest toe.
(C) Footprints shaped like a human’s that do not show a cross-stepping pattern exist at site M, which is a mile away from site G, and the two sets of footprints are contemporaneous.
(D) When the moist volcanic ash became sealed under additional layers of ash before hardening, some details of some of the footprints were erased.
(E) Most of the other footprints at site G were of animals with hooves.
Source: LSAT
the reason (D) is incorrect is that neither paleontologist weighs in on the issue of how much evidence you need to support a conclusion. That is, the disagreement is about what can be inferred from the evidence, not about whether there is enough evidence to draw any conclusion.
B-->, we have to make sure we understand the evidence brought up in the stimulus. It appears that the footprints discovered, though similar in shape to humans', differs in an important way: the "left" foot is on the right, and the "right" foot is on the left. As Dr. Rees says, for hominids to make those footprints, they would have to walk in a bizarre cross-stepping pattern.
Now if it turns out that a certain species of bear has footprints very similar to humans', except the order of the toes is reversed, then those bears would leave footprints just like the ones in question. (Look at your feet. If your big toe and little toe switched places, your right foot would look more like a left foot, and vice versa.) So if (B) is true, then it's much more likely that the footprints were left by bears than by early hominids, so Dr. Tyson's conclusion is weakened.
_________________
When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long