Which is the best version of the underlined portion of sentence 2 (reproduced below)?
These spiders don’t simply scurry across the sand on their many legs, like tumbling gymnasts, they propel themselves forward (or backward) in a series of quick flips.

A semicolon after “legs” results in two clear and complete independent clauses and a complete, logical sentence. Choice A is incorrect because a comma after “legs” results in a comma splice. Choice B is incorrect because a semicolon after “gymnasts” illogically suggests that scurrying across the sand on many legs is something that gymnasts would do. Choice D is incorrect because a comma after “gymnasts” results in a comma splice and illogically suggests that scurrying across the sand on many legs is something that gymnasts would do.