21. A chemical bond formed by the transfer of electrons is a(an)
bond. (1 point)

i tried the eyeshadow trick you told me about and it worked so good i i did a yellow going into orange colors and it was bright and you could see it on my eyes

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave