Hey there :)
It is called myxedema
It is the disposition of mucus polysaccharides in the dermis resulting in swelling of the affected area
Myx (mucus) + edema (swelling)
Each of a Number of small areas of habitat, typically of one square meter, selected at random to act as samples for assessing the local distribution of plants or animals.
Answer:
I am guessing The second Cause only petroleum stay in the top of water
