Dart in $1925 $ found the skull of a body whom he named

$A$ : Blood group analysis shows the human beings are more closely related to apes than to monkeys.
$R$ : The blood groups $A$ and $B$ are found in apes but not in monkeys.

Russian scientist who proposed the theory of origin of life was

Fossil $X$ is older than fossil $Y$ if

Darwin proposed that new species evolve from ancestral forms by the