Please choose the correct answer to the question: Fossils of clam shells were found in the Appalachian Mountains. Which of these statements best explains why the clam shells were found in the Appalachian Mountains?

Answer1: The mountain range was once under water. Answer2: Birds flying overhead dropped the clam shells. Answer3: Animals released the clam shells in their waste. Answer4: The clams lived on land before moving to water.

Answer format: answer1/answer2/answer3/answer4
Answer: answer1