How is the mass number calculated for an atom involved in nuclear fusion?

Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in the n=3 level to an orbital in the n=7 level.

This chart lists four kinds of polymers and their sources. what can be known about all four polymers, despite their differences? they come from living things. they share ionic carbon bonds. they are at least 100 monomers long. they are made of repeating subunits.

How can carbon move from "land" to bodies of water? describe the way human impact has lead to increased levels of co2 in the atmosphere.