microscope.
A telescope is the most helpful tool when observing the moon.
A hand lens would be the most useful tool for observing the details of an insect's wings. It allows for magnification, enabling you to see fine structures and patterns that would be difficult to discern with the naked eye. The other tools, such as a thermometer or balance, are not designed for detailed visual observation, while a graduated cylinder is meant for measuring liquid volumes.
The most useful tool would have to be diamond pickaxe.
bow and arrow
An eye.
my vibrator
Perhaps the most useful tool in tracking tornadoes is Doppler radar.
A healthy living human brain.
when is the estimation of product is a useful tool
the too that is most useful in word is the print because it allows you to print out what ever you want....
Control Charts
A useful tool would be a spatula.