What is the meaning of selective premeable

Selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell. ... Movement across a selectively permeable membrane can occur actively or passively. For example, water molecules can move passively through small pores on the membrane.

Explanation:

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.