Projections of population growth. World population estimates from 1800 to 2100, based on high, medium and low United Nations projections in 2015 and UN historical estimates for pre-1950 data.
Answers. Best Answer: Cell-to-Cell communication is absolutely essential for multicellular organisms. The billions of cells of a human or an oak tree must communicate in order to develop from a fertilized egg and then survive and reproduce in turn.Communication among cells is also important for many unicellular organisms that must locate food and find mates in order to sexually reproduce.he process by which a signal on a cell's surface is converted into a specific cellular response, a series of steps called a signal-transduction pathway, has been extensively studied in many types of cells.
Nerve cells need to be able to send messages to each other quickly and clearly. One way that nerve cells communicate with their neighbors is by sending a burst of small neurotransmitter molecules. These molecules diffuse to the neighboring cell and bind to special receptor proteins in the cell surface. These receptors then open, allowing ions to flow inside. The process is fast because the small neurotransmitters, such as acetylcholine or serotonin, diffuse rapidly across the narrow synapse between the cells.