Introduction:
The depth of the sea is a crucial factor that determines the distribution of algae. Algae are a diverse group of photosynthetic organisms that can be found in various aquatic environments. When it comes to the deepest waters of the sea, certain types of algae are more likely to be found. To understand which algae are likely to inhabit the deepest waters, we can refer to page 223 of the NCERT Biology Class 12 textbook.

Red Algae:
Red algae, also known as Rhodophyta, are one of the major groups of algae. They are found in marine environments and are capable of living in different depths of water. However, red algae are not commonly found in the deepest waters of the sea. They are more commonly found in shallower regions, where sunlight can penetrate the water.

Green Algae:
Green algae, also known as Chlorophyta, are another important group of algae. They are found in various aquatic environments, including freshwater and marine habitats. Green algae can tolerate a wide range of depths, from shallow to moderately deep waters. However, they are less likely to be found in the deepest waters of the sea due to their preference for well-lit areas.

Brown Algae:
Brown algae, also known as Phaeophyta, are the most likely type of algae to be found in the deepest waters of the sea. They are well-adapted to low light conditions and can survive in the absence of direct sunlight. Brown algae have specialized pigments that allow them to capture light more efficiently, even in deep waters. This adaptation enables them to thrive in the deeper regions of the sea where sunlight is limited.

Conclusion:
Among red, green, and brown algae that inhabit the sea, brown algae are more likely to be found in the deepest waters. Their ability to tolerate low light conditions and their specialized pigments make them well-suited for survival in the absence of direct sunlight. This adaptation allows brown algae to thrive in the deeper regions of the sea, where other types of algae may struggle to survive.