Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.

$(a)$ Salvinia    $(b)$ Opuntia     $(c)$ Rhizophora    $(d)$ Mangifera

Ratio between mortality and natality is called

Phenotypic variants formed in a population due to change in environment are called

$A$ : Holistic approach explains the environmental interactions.
$R$ : All environmental factors are integrated with no limits of time and space.