Why do the parts of the rocket come off in space?

Rocket parts, such as stages and boosters, are designed to detach in space to reduce weight and improve efficiency. As each stage uses its fuel, it becomes heavier with empty tanks, so shedding these parts allows the remaining stages to accelerate more effectively. This process helps the rocket achieve the necessary speed and altitude to reach its destination, such as orbit or another celestial body. Additionally, it prevents the risk of collision with discarded components during flight.