How does a Rapid growth pyramid become a Slow growth pyramid?

Slow or Stable Growth Population Pyramid

Explanation:

Only after the upper ages do you see a marked change in population. This type of population pyramid is mostly found in developed countries sometimes middle income countries. These countries have good health care, long life expectancies and stable governments.

an economic of depression

i'm sure the answer you are looking for would be

a. an ice age

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