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.
In the mesopelagic zone (or the twilight zone), there isn't enough sunlight for photosynthesis to occur. Therefore, plants cannot grow and and fewer animals are able to survive in this zone. Also, a major thermocline takes place in this layer, dropping the temperature from 20 Â°C to approximately 4 to 2 Â°C.