Final answer:
The narwhal has a dark body, a tail that is half the length of its body, and a single tusk that can grow up to 9 feet long.
Step-by-step explanation:
The narwhal, a species of whale, can be described by several characteristics. It has a dark body and its tail is approximately half the length of its body. The narwhal also has a single tusk that can grow up to 9 feet long, which is actually an elongated tooth. This tusk is unique to male narwhals and is believed to be a sensory organ used for navigation and mating purposes.
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