Which animal can puff up to twice or three times its size when scared?

Which animal can change the color of its skin to match its surroundings?

Which animal communicates with others using a language made up of whistles and clicks?

Which animal has a skeleton made entirely of flexible cartilage?

Which animal can hold its breath for up to 7 hours?

Which animal has 18 venomous spines on its back, fins, and tail?

Which animal has a hard skeleton located on the outside of its body?

Which animal is the most important for building reefs?

Which animal is related to sharks but does not have sharp teeth?