Walking Past a Pond in Olympic National Forest,you Spot the Head

Multiple Choice

Walking past a pond in Olympic National Forest,you spot the head of an animal that is swimming through the water.You can clearly see that the animal has fur but can't see anything else.Based on your observation,you know that the animal is a

A) vertebrate.
B) mammal.
C) bird.
D) vertebrate and a mammal.
E) vertebrate and a bird.