Consider the illustration of the cell cycle. what is the purpose of the areas labelled checkpoint in the cycle? all but one could apply.

Pluto was once classified as a planet. however, scientists no longer classify pluto as a planet. which is a likely reason for this change? the original hypothesis about pluto was supported. no observations of pluto were made in the past. several planets in outer space were found to be similar to pluto. there were significant changes in scientific knowledge about planets.