Filler Metal is a type of metal used in the fusion welding union, and it is necessary to produce a joint because it serves to collaborate in the opposition, to a greater or lesser degree, against the forces applied to it, without suffering deformation or breakage.
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
The answer is B hope it helps pls mark branliest
