Explain why the earth is not perfectly spherical

But it is very close to a perfect sphere.

The longest diameter - the line through the center of the earth whose endpoints are on the equator - is only 0.3% (3/10 of one percent) longer than the shortest diameter that goes between the poles. And the variation in the surface from the highest point above sea level (the top of Mt. Everest) to the lowest point below sea level (in the Marianas Ocean Trench off the coast of Japan) is only about 0.15% of the mean diameter of the earth.

Yes, technically it is an imperfect oblate spheroid due to its rotation about its axis which causes it to bulge a bit. But it is very close to a perfect polished sphere.

It was not.

Explanation:
After China implemented the “one child only” policy, it met a struggle from rural families who only wanted sons. Which caused girls getting killed, aborted, or forced into adoption. It also caused millions and millions of children to go undocumented, meaning they basically don’t exist. They got denied help from most government services, mostly likely never receive education or even healthcare. Since many parents were unable to pay the expensive second-child find. This might have been there only option.