This is just an educated guess. As the purple pigment, caused by anthocyanins, are on the bottom side of the plant, their purpose could probably be to direct the light.
Specifically, a purple pigment on the bottom of the plant would absorb certain wavelengths near the purple spectrum, and reflect other wavelengths back toward the portion of the plant with chlorophyll. In this way, light does not simply pass through the leaf, instead it is reflected back in towards the chlorophyll to maximize the amount of light being used for photosynthesis.
<span>The gum is probably lodged in the right primary bronchus. The right primary bronchus is an airway directly connected to the right lung. Bronchi are primarily responsible for moving air into the lungs, so when Keri choked on the gum, the gum would have blocked the air passage way required to breathe.</span>
