Here's why:

* Sunlight intensity: Sun plants are adapted to thrive in high-light conditions. They have more chlorophyll to capture the abundant sunlight for photosynthesis.

* Efficiency: The increased chlorophyll allows sun plants to produce more energy from sunlight, which is essential for their growth and survival.

* Shade plant adaptation: Shade plants have evolved to function efficiently in low-light environments. They have less chlorophyll to prevent overloading in the limited light available.

Think of it this way: Sun plants are like efficient solar panels designed for intense sunshine, while shade plants are like low-power solar panels that can still function in dimmer conditions.