Please choose the correct answer to the question: A species of bird has not been seen since the 1900s and is considered extinct. Which evidence would best disprove the claim that the bird is extinct?

Answer1: A bird watcher makes a sketch of the bird. Answer2: A scientist discovers fossil remains of the bird. Answer3: A researcher takes a photograph of the bird. Answer4: A park ranger finds a suitable habitat for the bird.

Answer format: answer1/answer2/answer3/answer4