Define/Explain: Ecotype.

$I.$ 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.

Explain how ecology is related to an organism?

$I.$ Biochemical adaptations are seen in organisms living at great depths of the ocean to face crushing pressure.
$II.$ Allen's rule explains adaptations in mammals living in colder climates.
$III.$ Altitude sickness is caused because the body does not get enough oxygen due to low atmospheric pressure at high altitudes.
$IV.$ Desert lizards lack behavioural means to manage their body temperature.
Choose the correct option for the above statements.

Animals that move about or swim about in the sea are known as:

Plants that grow in water are known as: