If electrons fall back down to the 2nd energy level, what type of electromagnetic radiation is released?

Who is better, messi or cristiano, i need this for a chemistry class. asap

Why does earth rotate? because earth is formed from cold gases collapsing due to gravity because the matter in the nebula that formed earth was spinning because earth forms more than 99% of the mass of the solar system because the hydrogen atoms inside the nebula fused to form helium

Na chemical reaction, activation energy increases the of the reactants. this outcome causes the particles to collide, which results in the of new products.