All cells have a nucleus that acts as a command center for the cell.

Yes

Explanation:

The nucleus is the main part of the cell because it acts like the brain/commander of the cell

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.