Phrase 'Survival of the Fittest' was used by

The early stage human embryo distinctly possesses

$A$ : Sometimes, some babies have a small tail.
$R$ : This is just a type of mutant variety

Stings of honey bee and the stings of scorpion are

$I.$ analogous organs

$II.$ heterologous organs

$III.$ homologous organs

$IV.$ vestigial organs

The correct combination is

Assertion : Comparative biochemistry provides a strong evidence in favour of common ancestory of living beings.

Reason : Genetic code is universal.