Pratik was performing an experiment to test for the presence of starch and glycogen in different types of foods. He treated four food samples with a Lugol's
iodine reagent. This solution is brown-yellow, but it produces a blue-black color
when it reacts with starch and a brown-blue color when it reacts with glycogen.

straight or amphibians are homeothermic to thermal

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