What single physical principle does the source say explains rockets, jet engines, deflating balloons, and even squids and octopuses moving through water?

1. The source names one law of motion as the common explanation for all of these examples. 2. It states that this propulsion is explained by the same physical principle, Newton's third law of motion. 3. Matter is forcefully ejected from each system, producing an equal and opposite reaction on what remains. 4. Newton's first law, energy conservation alone, and buoyancy are each different physical ideas not credited with explaining this shared propulsion mechanism. _Source: OpenStax College Physics (CC BY 4.0), Ch 8 "Linear Momentum and Collisions", section 8.7 Introduction to Rocket Propulsion_