And what that means is we consist of many, many, many individual cells. Now, for the human to actually function correctly the individual cells must be able to work together and they must be able to communicate with one another. And on top of that, these individual cells must be able to carry out the processes at the correct time. And the question is, is how does a given cell actually know to carry out a specific set of processes at a given time? So to demonstrate what I mean by that, let's imagine the following scenario and we're going to use this scenario as we go along this lecture. So let's suppose I'm walking in the national park and I come across a bear and that bear happens to be hungry.