Used to lift heavy objects by changing the direction or amount of force
The function of a lever is used to move or lift objects.
For Somethings
It is used to lift a heavy object. Place the end of the lever under the rock. Then move a fulcrum (for example a small rock) under the lever close to where it goes under the rock. By moving your end of the lever a lot, you can make the shorter end move a little and lift a heavy weight.
Block and tackle refers to a rope threaded through a series of pulleys to provide mechanical advantage, and it is used to lift heavy objects,
Used to lift heavy objects by changing the direction or amount of force
The function of a lever is used to move or lift objects.
because we can't lift it with our hand
Both, and neither. Both, because levers successfully assist people in lifting heavy objects (which requires force) and opening things (which requires force). Neither, because the definition of a lever has nothing to do with how the theory is used.
For Somethings
It is used to lift a heavy object. Place the end of the lever under the rock. Then move a fulcrum (for example a small rock) under the lever close to where it goes under the rock. By moving your end of the lever a lot, you can make the shorter end move a little and lift a heavy weight.
Biceps function to lift your forearm up to touch your shoulder. They are often used in cooperation with the muscles in your back to lift heavy objects.
Water
The pulley was discovered to lift objects that would otherwise be too heavy to lift. Much in the way a crane is used to lift cargo onto ships.
A spatula is used as a lever when it is used to lift a substance from a surface.
A screw jack is an object that is used to lift the car and other heavy objects off the ground.
I am not quite sure what you mean. To move heavy objects, you need a strong force - and that requires energy. Gold doesn't help with that - unless you pay somebody in gold to do it for you. A strong force can be achieved with a lever. If you want to construct your lever out of gold, you're certainly entitled to do that.