The correct answer is A. halophytes.
Halophytes are plants that have adapted to grow in saline water. They have a number of adaptations that allow them to tolerate the high salt concentration, including:
- Salt glands: These glands excrete excess salt from the plant.
- Thick cuticles: These waxy coatings help to prevent water loss.
- Succulent leaves: These leaves store water and help to reduce water loss.
- Aerenchyma: This is a tissue that contains air spaces, which helps to reduce the density of the plant and prevent it from sinking in the water.
Halophytes are found in a variety of habitats, including salt marshes, mangrove swamps, and saline lakes. They play an important role in these ecosystems, as they help to stabilize the soil and provide food and shelter for other organisms.
Option B, hydrophytes, are plants that grow in water. They have a number of adaptations that allow them to tolerate the lack of oxygen in water, including:
- Aerenchyma: This is a tissue that contains air spaces, which helps to provide oxygen to the plant.
- Thin cuticles: These waxy coatings allow water to pass through more easily, which is important for plants that are constantly surrounded by water.
- Large leaves: These leaves help to absorb more sunlight, which is important for plants that are not able to photosynthesize as efficiently in water.
Option C, mesophytes, are plants that grow in moist, but not wet, environments. They have a number of adaptations that allow them to tolerate both wet and dry conditions, including:
- Medium-sized leaves: These leaves help to balance the need for sunlight and the need to avoid water loss.
- Thin cuticles: These waxy coatings allow water to pass through more easily, which is important for plants that are not able to photosynthesize as efficiently in dry conditions.
- Roots: These roots help the plant to absorb water and nutrients from the soil.
Option D, thallophytes, are a group of plants that do not have true stems, leaves, or roots. They include algae, mosses, and liverworts. They are found in a variety of habitats, including aquatic environments, soil, and on rocks.