What characteristic fundamentally sets the moose's classification as a mammal?

Answer

Feeding its young with milk produced by mammary glands

Being a mammal means the moose is warm-blooded, breathes air with lungs, has hair or fur, and feeds its young with milk produced by mammary glands, which is a defining characteristic.

What characteristic fundamentally sets the moose's classification as a mammal?
animalmammalclassificationwildlifemoose