Splint bones in the front legs of horses serve only to absorb shock to the front feet. This shock is generated only because horses run. Thus, the fact that Eohippus, an ancestor of the horse, has similar bones in its front legs provides evidence for the hypothesis that Eohippus moved by running, not just by walking.
Which of the following, if true, most seriously weakens the argument in the passage?
(A) Eohippus' splint bones were far more similar to the splint bones of modern horses than to the splint bones of elephants, which usually walk.
(B) It is unknown whether ancestors of the modern horse other than Eohippus had bones similar to splint bones in their front legs.
(C) The mechanism used by horses for absorbing shock could, theoretically, work for similar creatures such as Eohippus.
(D) Not all horses that have splint bones to absorb shock live in regions where the hardness of the ground is similar to that in the regions inhabited by Eohippus.
(E) Other ancestors of the horse that moved only by walking had bones in their front legs similar to those that Eohippus had.
Please explain your answer!
Which of the following, if true, most seriously weakens the argument in the passage?
(A) Eohippus' splint bones were far more similar to the splint bones of modern horses than to the splint bones of elephants, which usually walk.
(B) It is unknown whether ancestors of the modern horse other than Eohippus had bones similar to splint bones in their front legs.
(C) The mechanism used by horses for absorbing shock could, theoretically, work for similar creatures such as Eohippus.
(D) Not all horses that have splint bones to absorb shock live in regions where the hardness of the ground is similar to that in the regions inhabited by Eohippus.
(E) Other ancestors of the horse that moved only by walking had bones in their front legs similar to those that Eohippus had.
Please explain your answer!
