Name all of the planets people have walked on

Fill in the blank. the number of each type of element in the compound (other than 1) is represented by a small number to the right of the element symbol.

Describe different biomes. what are some adaptations that organisms (plants or animals) must have to live in each biome?

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?