Final answer:
The largest animal that ever lived is the Blue whale.
Step-by-step explanation:
The largest animal that ever lived is the Blue whale (a). Blue whales are the largest living vertebrates and can reach lengths of up to 110 feet. They are found in oceans around the world and are known for their massive size and incredible weight, which can exceed 200 tons. Their size and adaptations make them highly efficient filter feeders, consuming enormous amounts of krill to sustain their energy needs.