‘Eco’ term refers as

$A$ : Population ecology is a link of ecology to population genetics and evolution.
$R$ : Natural selection operates at population level to evolve the desired traits.

Smallest unit of ecology is

Species which occupy a similar ecological niche in similar communities occupying different biogeographical regions are

Ecological equivalents meant for

Ruthless exploitation and pollution of the environment has increased the magnitude of waste materials which has disturbed the operations of all important