Now, cells generally respond to morphogens based on the level or the concentration of that morphogen found in that local environment. And to see what we mean by that let's take a look at the following diagram. So we have cell number one and cell number two. Notice these cells on their membranes contain these special protein receptors that can actually bind these Morphins, these special signal molecules. Notice on the left side we have a much higher concentration of these morphogens than on the right side. And because we have many more of these mortgagen molecules around this cell these signal molecules will be much more likely to actually bind onto the receptor protein than on this cell.