What are glacial erratics made/composed of? how did they form?

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?

Ahydrogen atom has 1 electron. how many bonds can hydrogen form? a) 1 b) 2 c) 3 d) 4 e) 5

Gwhich r group would most likely be found in a hydrophobic area of the tertiary structure of a globular protein? which r group would most likely be found in a hydrophobic area of the tertiary structure of a globular protein? −ch2−oh −ch2−o||c−nh2 −ch2−coo− −ch2−ch2−ch2−ch2−n+h3