How many total levels are on the population pyramid?

A population pyramid, also called an "age-gender-pyramid", is a graphical illustration that ... It is also used in ecology to determine the overall age distribution of a ... This ratio refers to how many old and young people are dependent on the ... countries have a population represented by the pyramids in stages one and two.

Explanation:

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b. martin luther king jr. wrote and spoke "i have a dream"

explanation:

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