What year did Clara Baer invent Nukem/Newcomb ball?

The earth remains in orbit around the sun due to the force of gravity. how does the force of gravity exerted by the sun on the earth compare to the force of gravity exerted by the earth on the sun?

Explain to someone who knows nothing about fossils the study of invertebrate paleontology and how it scientists understand the history of the earth. be sure your explanation contains a minimum of two complete sentences.

Ab+c --> ac+b is the general equation for which one of the following types of chemical reactions? a.) combination b.) single-displacement c.) decomposition d.) double-displacement