Answer:
Gravitational time dilation occurs because objects with a lot of mass create a strong gravitational field. The gravitational field is really a curving of space and time. The stronger the gravity, the more spacetime curves, and the slower time itself proceeds.
No idea about the scientific reasoning, but the leaves of the plant are where the most photosynthesizing has to happen. In order for the plant to get energy it has to absorb the most light. So it creates broad leaves. The reason they are green is because chloroplasts are green. I believe that the cells in the leaves have more chloroplasts so that they can catch more sunlight.<span />
That statement is true because The amount of energy at each trophic level decreases as it moves through an ecosystem at least is 10% of the energy at any traffic levels transferred to the next level the rest is lost largely through the metabolic process as heat.