What do you need to use in order to work as a environmental scientist?

You should be able to get an entry-level job with a bachelor's degree in environmental science but to advance in this field, a master's degree is required. Alternatively, you can begin your career with an undergraduate degree in biology, engineering, chemistry, or physics.

is this for the e2020 class

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.