Is the mustang horse an invertebrate or vertebrate?

Answer 1

The mustang horse is no different than any other horse if you're discussing vertebrae or invertebrae. All horses are vertebrae but how many bones are in the spine depends on the breed.

An animal is a vertebrate if they have a backbone/spine. So usually, any creature that has a skeleton is a vertebrate. Invertebrates don't have a backbone and usually have what is known as an extoskeleton (outer skeleton), such as insects or crabs. Therefore, the mustang is a horse and horses have spines = vertebrate.