Rainfall is absent but precipitation occurs in

$I.$ Many xerophytic plants have thick cuticle on leaf epidermis and sunken stomata.
$II.$ Some xerophytic plants have a special photosynthetic pathway $(CAM)$ that enables their stomata to close during the day.
$III.$ $Opuntia$ has spines (modified leaves) and a photosynthetic phylloclade (stem).
$IV.$ All adaptations are genetically fixed in all organisms.
Choose the combination of correct statements.

Many freshwater fishes cannot live in seawater and vice versa because of:

Deserts occur in areas of

Large size of pinnae in animals of warm regions in comparison to animals of cold regions is due to:

Alpine tundra is found in