1) High energy astrophysics deals with simpler objects like protons, neutrons, and electrons, while astrochemistry and astrobiology consider more complex structures like molecules, stars, and living organisms. 2) The scale and energy involved separates these disciplines - high energies probe smaller, simpler structures while larger, more complex objects require less energy. 3) Astrochemistry uses spectroscopy to study the composition of stars, interstellar gas, and planetary atmospheres and determine which elements are present. Astrobiology examines the potential habitability of exoplanets and moons.