Faced with mounting population pressure and the resultant drain on natural resources, many growing populations wish to migrate, and other dwindling nations import labor. Where are the major sources and destinations of this population growth differential in the world today? What issues do the immigrants bring with them?

the answer to your question is slate

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.