Contraclite vacuole is mostly present in Freshwater protozoa.

Freshwater Protozoa:
Freshwater protozoa are a group of single-celled organisms that inhabit freshwater environments such as ponds, lakes, and rivers. They are an essential part of the aquatic ecosystem, playing roles in nutrient cycling and serving as a food source for other organisms.

Contraclite Vacuole:
A contraclite vacuole is a specialized organelle found in certain protozoa, including some freshwater species. It is involved in osmoregulation, which is the regulation of water and solute balance within the cell.

Function of Contraclite Vacuole:
The contraclite vacuole helps maintain the internal balance of the cell by regulating the water content. It collects excess water and waste products from the cytoplasm and expels them from the cell, preventing the cell from bursting due to osmotic pressure.

Presence in Freshwater Protozoa:
Freshwater environments have lower solute concentrations compared to the cytoplasm of the protozoa. As a result, water tends to enter the cell by osmosis, leading to an increase in cell volume. To counteract this, freshwater protozoa have evolved the contraclite vacuole as a mechanism to remove excess water.

Marine Protozoa:
Marine protozoa, on the other hand, inhabit saltwater environments. These organisms face different osmoregulatory challenges compared to their freshwater counterparts. Marine protozoa generally have contractile vacuoles, which function similarly to contraclite vacuoles in freshwater protozoa but are adapted to the higher salinity of their environment.

Parasitic Protozoa:
Parasitic protozoa are protozoa that live inside or on another organism (host) and obtain nutrients from the host. They infect a wide range of organisms, including humans and animals. The presence of contraclite vacuoles in parasitic protozoa may vary depending on the specific species and their environment.

Conclusion:
In summary, contraclite vacuoles are mostly present in freshwater protozoa. These specialized organelles help regulate water and solute balance within the cell, preventing it from bursting due to osmotic pressure. Marine protozoa and parasitic protozoa may have different adaptations for osmoregulation depending on their specific environments and lifestyles.