👉 Protopods are a group of animals that have an exoskeleton or a hard shell, which allows them to survive in environments with extreme conditions such as cold, heat, and water. These animals often have soft tissues made up of keratin, which gives them their characteristic flexible body shape. Protopods can also be classified based on the type of shells they possess, including those that are covered in a hard outer layer called an exoskeleton (e.g., crustaceans), or