$A$ : Archaeopteryx had free caudal vertebrae and toothed beak with teeth like reptiles.
$R$ : It is missing link between reptiles and bird

Phenomenon of industrial melanism demonstrates

$A$ : Similarities in proteins and genes performing a given function among diverse organisms give clue to common ancestry.
$R$ : All the group of vertebrates arises from the common ancestor with great adaptation capability.

Ancestor of man, who first stood erect, was