Both use ion channels to move ions across the cell membrane, in or out of the cell. Differences: Passive Transport (or Diffusion) moves ions from high concentration to low, using no metabolic energy. Active Transport moves ions from low concentration to high, using metabolic energy in the form of ATP.
Birds have a hard time in cold weather, because their body temperatures are higher than those of humans They provide warmth and insulation against colder temperatures. Many birds grow extra feathers in the months leading up to colder weather, so that they'll stay warmer when temperatures drop.
A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. ... Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds.
