A population pyramid is a graph that allows us to see the gender and age structure of a population. There are different shapes to the pyramids which tell us different things about the population of the country. It is often useful to divide population pyramids into 3 distinct age groups or COHORTS- 0-15 or the Young, 16-65 or the working age and 65+ as the retired sectors of the population. Knowing the percentage of people in these sectors can allow us to calculate a Dependency Ratio. This is the ratio between those of working age and those of non-working age. The no-working age are known as DEPENDENTS because they depend upon the working age people to provide for their needs.
Why are areas along the west coast of California cooler than you would expect for their latitude? These areas are far from a large body of water. ... A cold ocean current travels along the coast.
