What are the two classes of pure substances?

Sarah is sitting at the top of the slide in the schools playground. which will increase sarah’s kinetic energy a- an additional child is added to the top of the slide. b- sarah is pushed and moves down the slide. c- sarah climbs down the ladder and off the slide. d- the ladder is moved to the other side of the yard.

Of seawater increases with decrease in the temperature. therefore, the cold water sinks to the deeper layers at the bottom

In the practice of science, this type of reasoning is used to develop explanations.