A tool is an object that can extend an individual's ability to modify
features of the surrounding environment or help them accomplish a particular
task, and proto-typically refers to solid hand-operated non-biological objects
with a single broad purpose that lack multiple functions, unlike machines or
computers. Although human beings are proportionally most active in using and
making tools in the animal kingdom, as use of stone tools dates back hundreds
of millennia, and also in using tools to make other tools, many animals have
demonstrated tool use in both instances.