Question

which animal uses a tool to protect itself from injury?
sea otter
green heron
woodpecker finch
bottle - nosed dolphin

Explanation:

Sea otters are known to use rocks as tools. They will float on their backs and place a rock on their chests, then use it to crack open shellfish. This behavior is a form of tool - use for protection (in the sense of accessing food which is crucial for survival) and obtaining resources. Bottle - nosed dolphins, woodpecker finches, and green herons do not typically use tools in the same way for protection - related (in terms of resource - access - for - survival which can be seen as a form of self - protection) purposes as sea otters.

Answer:

sea otter