How many parts does a simple machine have

answerhomologous structures;

reflection is the bouncing back of a propagating wave when it encounters a barrier; usually shows an image of the source of light wave

1) bounces back from an opaque material

2) bounces back from the boundary

3) seen in mirrors

refraction is the bending of a propagating wave having a shift of direction as it passes through different media; usually seen in lenses to magnify or lessen

1) passes through a prism

2) moves from one medium to another

3) seen in lenses