As thermal energy is added to the pigment, what is occurring within the pigments to create a color change?

thermochromism, too hot of temperature or long exposure to high temperature may completely degrade the color of an object. In other instances, an object or sample changes to another shade of color until it stabilizes back to room temperature.

Explanation:

petroleum? coal maybe?

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.