Name the famous plants ecologist

Define population and community.

Habitat together with functions of species constitute its

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

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

Community is

$I.$ Group of independent, interacting populations of same species

$II.$ Group of independent and interacting populations of same species in specific area

$III.$ Group of independent interacting populations of different species in a specific area

$IV.$ Group of independent and interacting populations of different species in different area

Select the correct option