It is a vertebrate because it has a spinal column in its skeletal system. Also it is a mammal, although it lays eggs, and every mammal (or other warm-blooded creature, like a bird) is a vertebrate.
The lancelet is an invertebrate.
The platypus is not an invertebrate. It is a vertebrate, a member of the Kingdom Animalia. It is a mammal, specifically a monotreme, or egg-laying mammal.
It is a mammal and all mammals are vertebrates because they have internal skeletons and backbones.
No, a platypus does not have scales. It has dense, sleek, waterproof fur.
invertebrate - has exoskeleton
An invertebrate.
a platypus's bill is a bill that is on a platypus
a platypus's bill is a bill that is on a platypus
no
It is an invertebrate 
A bullfrog is not an invertebrate; it has a spine.
The octopus is an invertebrate... It has no skeleton.