In terms of macromolecules, needed and utilized by organisms to carry out essential metabolic chemical reactions and for maintaining structure would be Lipids.
Lipid based molecules or Fats tend to store the most energy, as breaking chemical bonds connecting fatty acid chains of long hydrocarbons releases quite a bit of energy.
Tropical climate is a region of the earth surrounding the equator. When the earth is exposed to light from the sun it is right over the equator and up 23 degrees of latitude Tropic of Cancer in the northern hemisphere and Tropic of Capricorn in the southern hemisphere
Transpulmonary pressure, the difference between intrapulmonary and intrapleural pressures, prevents the lungs from collapsing
Group cells that have the same function are tissue