Acrossbow:
a. can shoot farther than conventional bows
b. shoots bolts or short arrows
c. has straight limbs that arc when the bow is strung
d. is the traditional bow

The answer is B.

Explanation:

A crossbow is a type of elastic ranged weapon in similar principle to a bow, consisting of a bow-like assembly called a prod, mounted horizontally on a main frame called a tiller, which is handheld in a similar fashion to the stock of a long gun. It shoots arrow-like projectiles called bolts or quarrels.

frequency or wavelenth of em radiation in a vacuum

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