Final answer:
The sentence that contains a comma splice is: To save the California condor, scientists trapped the surviving 27 birds and bred them in captivity, but the condor is still one of the rarest birds in the world.
Step-by-step explanation:
The sentence that contains a comma splice is:
To save the California condor, scientists trapped the surviving 27 birds and bred them in captivity, but the condor is still one of the rarest birds in the world.
A comma splice occurs when two complete sentences are joined by a comma without a coordinating conjunction or proper punctuation. In this sentence, the phrases 'scientists trapped the surviving 27 birds and bred them in captivity' and 'the condor is still one of the rarest birds in the world' are both independent clauses that should be separated with a coordinating conjunction or proper punctuation.