Which resource is a renewable resource?
coal
gemstones
metal
trees

Trees

Explanation:

As trees can be grown again.

trees

Explanation:

A renewable resource is one that you can extract and it will replenish (grow) back in a short amount of time (think a human generation or two, a range similar to 25-50 years).

Trees will regrow within that time if the land is left unused and there are still the proper conditions to grow.

Coal, gemstones and metal form over a period that is counted more like thousands of years, so you cannot simply return later to the same spot to find more, especially since they need specific conditions to form, and those conditions (like pressure) will not be there anymore.

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

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr