AP BIOLOGY

Detailed explanation-1: -The platypus was ultimately placed into a new order called Monotremata, alongside the four living species of echidna. Monotremes are, notably, egg-laying mammals that produce milk for their young.

Detailed explanation-2: -The platypus, classified as a mammal because it produces milk and is covered in a coat of fur, also possesses features of reptiles, birds and their common ancestors, along with some curious attributes of its own.

Detailed explanation-3: -The platypus is classed as a mammal because it has fur and feeds its young with milk. It flaps a beaver-like tail. But it also has bird and reptile features-a duck-like bill and webbed feet, and lives mostly underwater. Males have venom-filled spurs on their heels.

Detailed explanation-4: -A platypus is classed as a mammal because it has fur and feeds its offspring milk, yet it lays eggs, which is uncommon for mammals but not for other vertebrates.

Detailed explanation-5: -Mammals are a group of vertebrate animals. Examples of mammals include rats, cats, dogs, deer, monkeys, apes, bats, whales, dolphins, and humans.