select the choice that best completes the following sentence.

simple machines,

a. are made up of multiple moving part.

b. reduce the amount of energy needed to do work.

c. cannot be combined to make compound machines.

d. are tools that make work easier.

Its B: reduce the amount of energy needed to do the work by putting the work onto something else

The answer is be because they do simplr jons for you and you dont have to worry about wasting energy on it

(mark me as brainliest)

0.863333

86%

hope this

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia