What do scientists find out when they trace the ancestors of dogs and cats?

  1. All dogs and cats living today share a common ancestor with each other that lived a very long time ago.
  2. All dogs share a common ancestor with each other, and all cats share a common ancestor with each other, but cats and dogs do not share a common ancestor with each other.
  3. Some dogs share a common ancestor with some cats, but all cats and dogs do not share a common ancestor with each other.
  4. Scientists cannot trace the ancestors of any two species back far enough to find out whether they had a common ancestor with each other.

Distribution of Responses

Chart showing distrubtion of responses for Item EN049002

Percent of students responding correctly

Overall27%
Grades 6–823%
Grades 9–1232%
Male29%
Female24%
Primary Language is English26%
Primary Language is not English28%

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