Conserved quantities play a crucial role in physical systems by reflecting underlying symmetries, as described by Noether's Theorem. The conservation of energy is essential for the equations governing lossless harmonic oscillators, where the total energy remains constant. Momentum conservation arises from spatial symmetry, while energy conservation is linked to temporal symmetry, and angular momentum conservation is associated with parity symmetry. These principles help in understanding the behavior and dynamics of various physical systems. Overall, conserved quantities provide foundational insights into the laws governing motion and energy.