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.
Communication between animal cells can be carried out through three types of junctions. The first, a tight junction, is a watertight seal between two adjacent animal cells . The cells are held tightly against each other by proteins (predominantly two proteins called claudins and occludins).