The rock record indicates that photosynthesis began on Earth about 3.5 million years ago.

When electrons are added to the outermost shell of a carbon atom, it forms--an anion that has a larger anion that has a smaller cation that has a larger cation that has a smaller radius.

How many neutrons does plutonium -196 with an atomic number of 78.

Ahorizontal force of 400.0 n is required to pull a 1760 n truck across the floor at a constant speed. find the coefficient of sliding friction.