What property prevents the ligands of cell-surface receptors from entering the cell?
the molecules bind to the extracellular domain.
the molecules are hydrophilic and cannot penetrate the hydrophobic interior of the plasma membrane.
the molecules are attached to transport proteins that deliver them through the bloodstream to target cells.
the ligands are able to penetrate the membrane and directly influence gene expression upon receptor binding.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate

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.

c.           is the correct answer

answer denitrification;