How does the Peppered Moth demonstrate natural selection?

The Peppered Moth demonstrates natural selection by the rapid change in appearance due to pressure on the Moth to adapt. When pollution was high, trees turned black from soot, this caused the white moths to be easily targeted as prey, but darker moths survived. This changed the general phenotype of the Peppered moth population. When the Clean Air Act was established, and pollution lessened, the white moth variation started to appear again.

How does the electromagnetic spectrum allow scientist to study stars/planets from a distance?

Each element has a specific light emission pattern. Scientists can use the electromagnetic spectrum to identify what elements are present in stars and planets based on the specific light pattern they emit.

How do plant cells react in hypertonic and hypotonic solutions?

Plant cells use osmosis and diffusion to react to hypertonic and hypotonic environments. Lets use a carrot as an example. If you place a carrot in saltwater (a hypertonic solution) the carrot will lose water. Water is drawn out from the cells and into the saltwater in an attempt to create equilibrium. This will dehydrate the carrot. If the carrot is in freshwater ( a hypotonic solution) the water will enter the carrot cells, because the carrot has a higher concentration of solutes than the water. This will cause the carrot to swell and become rigid.