This is because twilight or mesopelagic zone (extending from 200 meters to 1,000 meters) is the zone that contains the thermocline.
A thermocline or the thermal layer is a layer in an ocean or lake where the temperature changes more rapidly with depth than in the other layers. The thermocline in twilight zone divides the upper mixed layer from the calm deep water below.
<span>Proteins secreted by epithelial cells. The basement membrane forms as a thin protein fibre membrane with mucopolysaccharides. It separates an epithelium from underlying tissue. Its main function is to anchor epithelium to dermis underneath. The membrane consists of different extracellular matrix structural proteins.</span>
