Changes in stool color alone do not cause symptoms. The underlying cause of the change in stool color, texture, or form is responsible for any symptoms. Bowel movements are usually light to dark brown in color, and there is moderate variation among individuals with respect to stool color, quantity and form.
Plants in the Twilight Zone As the amount of light decreases, the size and complexity of plant life also decreases. So whereas there may be flowering plants growing in the entrance zone, the twilight zone is typically marked by mosses and ferns.
Diet: Animals in this zone feed on plant matter and algae that fall into this zone from the euphotic zone (the well-lit zone above the disphotic zone), animals that stray into this twilight zone, and each other. Animals in the disphotic zone are filter feeders, grazers, and predators.n average, this zone extends from 660 to 3,300 feet (200 to 1,000 m). In the disphotic zone, there is enough light to see during the day, but not enough light for photosynthesis to take place, so no plants live in this zone. The amout of light decreases with depth.