Amy throws a softball through the air. what are the difference forces acting on the ball whilt it's in the air?

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?

Earth's atmosphere is composed of mostly two gases. name the two gases that make up the majority of the atmosphere and use the pie chart to tell the percentages of each.

What is part of a line has one endpoint and continues in one direction?