Given below some major events in the early history of life
$I.$ First heterotrophic prokaryotes
$II.$ First eukaryotes
$III.$ First autotrophic prokaryotes
$IV.$ First animals
Choose the correct sequence of these evolutionary events
$IV, III, II, I$
$I, III, II, IV$
$I, II, III, IV$
$IV, I, II, III$
The homologous organs are
Vestigial organ in man is
The golden age of Dinosaurs was in which of the following era
$A$ : India falls under oriental realm out of other biogeographical realms.
$R$ : World is divided in six biogeographical realms.
Replacement of original hard parts or even the soft tissues of the organisms by minerals is known as