The dinosaurs descended from . . . . . . ancestors.

$A$: The brain reaches between $75$ and $80$ percent of its adult size within the first two years,and its full size at the age of $6$ years.
$R$: From an evolutionary point of view,the human gestation period is believed to be shortening.

Modern $Homo$ $sapiens$ arose:

$Homo$ $sapiens$ $neanderthalensis$ and $Homo$ $sapiens$ $sapiens$ ($Cro-magnon$ man) originated from:

Which of the following is the correct chronological order of the evolutionary history of man?

Which of the following represents the correct chronological order of human evolution from the earliest to the most recent?