Q3 of 70 Page 92

Why do all the freshwater organisms have contractile vacuoles whereas majority of marine organisms lack them?

Contractile vacuole helps in removal of excess water from the body. Marine fish are exposed to high salinity. So, there is no need to remove excess water as osmotic balance between the surrounding water and fish’s body is maintained. Fresh water fish are exposed to low salt concentration. So, they require contractile vacuoles to remove excess water.


More from this chapter

All 70 →
1

Why are coral reefs not found in the regions from west Bengal to Andhra Pradesh but are found in Tamil Nadu and on the east coast of India?

 2

If a freshwater fish is placed in an aquarium containing sea water, will the fish be able to survive? Explain giving reasons.

 4

Define heliophytes and sciophytes. Name a plant from your locality that is either heliophyte or sciophyte.

 5

Why do submerged plants receive weaker illumination than exposed floating plants in a lake?