There are many fish and other large marine animals in the light zone becuse plankton (a main foodsource for many fish) is able to grow.
b:failure of pituitary gland to secrete ADH .caauses diabetes inspidus.
c:located at the kidney.cortex dark in colour and its the outermost.medulla red in colour and lies at the centre.
In gilled mushrooms, gills are used to maximize spore production. Gills of some mushrooms are folded and crowded to obtain maximum spore production. Other gills, spread towards the outer cap which gives way to new gill growth in between gills which is called partial gill. Some of the mushrooms grow gills in layers too.
In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area that was previously occupied by living things is disturbed, then re-colonized following the disturbance.
Hope this help