The second answer
Temperatures up high need to be warmer near the surface, surface air needs to be humid
Women are more likely than men to get UTIs because the urethra is shorter in a woman than in a man. So I believe it is structure 2.
Nucleic acids also typically contain phosphorous, and nitrogen plays an important structural role in nucleic and proteins. The proteins, being made up a diverse set of amino acids, have, in addition to carbon, hydrogen, oxygen, and nitrogen, the elements sulfur and selenium.
temperature never stays the same on a day to day basis
Heat you can turn on and off
Thermal energy is something that you can well control on your own by yourself