How does youthful population pyramid indicates growing population but aged population a decreasing population Please tell me correct answer

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In more developed countries, the population pyramid seems to get smaller and smaller in at the bottom, and larger at the top. This is due to two reasons:

A) Increased life expectancy, and

B) Lower overall birth rates.

the answer is:

c. islam and christianity

explanation:

islam and christianity are widely practiced in africa. islam is practiced due to its spread from the middle east into africa, and christianity is practiced due to the colonization of africa by the british empire.