Compare the shape of the darkest blue pyramid that represents the structure of the world population in $1950$ to the green pyramid for $2018.$ Which of the following statements are true? $($You may select more than one$).$

The strong narrowing of the $1950$ pyramid indicates that many children did not survive to adulthood. The shape of the green pyramid does not narrow until it is taller, indicating that more children survived to adulthood in $2018$ than $2050.$

The narrowing of the $1950$ pyramid indicates that men lived longer than women in $1950,$ but that was no longer true in $2018.$

The difference in the shape of the darkest blue pyramid $($representing $1950)$ and the green $($representing $2018)$ indicates that there was a higher instance of childhood illness in $2018.$

The difference suggests there were more children in $2018$ than $1950.$