Answer the following question: You are presented with the question "What can secrete an exoskeleton that builds up to become a reef?" and the following answer choices: - graptolites - some invertebrates - remains of prehistoric life - humans - insects - gastropod shells - barnacles - all invertebrates Now knowing that many corals secrete an exoskeleton that builds up to become a coral reef and corals, and invertebrates in general, are delicate creatures, choose the best answer.
Answer:
some invertebrates