If you are examining rock layers that are suspected to be about 20 million years old, which radioactive isotope would you use? Explain your answer

Scientists usually use the potassium-argon method to date rocks that are older than about 1 million years. Uranium-238 is also used for radiometric dating.

the elements of art are the visual tools that the artist uses to create a composition. these are line, shape, color, value, form, texture, and space.

the principles of art and design are balance, contrast, emphasis, movement, pattern, rhythm, and unity/variety.

the planets have a circular orbit around the sun.