The correct option is (c).
Explanation
Organisms possess specific physiological and morphological features that enable them to survive in their particular habitats. This process is known as adaptation. The marine environment is characterized by high salinity (salt content), whereas terrestrial environments like deserts are characterized by water scarcity.
Statement-wise Analysis:
- Statement 1 is Incorrect.
The sea contains saline (salty) water due to dissolved salts. Consequently, aquatic plants and animals living in the sea are surrounded by saline water, not fresh water. They possess specific physiological adaptations to manage the high osmotic pressure of their environment. - Statement 2 is Correct.
Most marine organisms (such as fish, crustaceans, and mollusks) respire by extracting oxygen that is dissolved in the water. They typically use specialized organs like gills to facilitate this gas exchange. While some marine animals like whales and dolphins breathe atmospheric air, the statement correctly notes that "most" use dissolved air. - Statement 3 is Correct.
Camels are terrestrial mammals specifically adapted to xeric (desert) environments. Their adaptations include water conservation mechanisms (concentrated urine, dry dung) and padded feet for walking on sand. They are not adapted to the saline aquatic environment of the sea; they lack the necessary osmoregulatory mechanisms to handle constant saltwater immersion and the morphological features (fins, gills) required for an aquatic habitat.
Key Takeaway:
Adaptation is habitat-specific. Marine organisms are adapted to high salinity and dissolved oxygen, while terrestrial organisms like camels are adapted to air breathing and water conservation in dry environments.