THE MECHANISM OF MARINE EROSION
The most powerful agents of marine erosion are waves. Their origin is due to the sweeping of winds over the water surface, which sets a series of undulating swells surging forward. These become higher and swifter. A normal wave in…
THE ACTION OF WAVES, TIDES AND CURRENTS
The action of the wind passing over a stretch of sea causes waves to develop and when the waves reach the coast they cause erosion or deposition. Wind passing over water sets up turbulences, which causes ripples and then waves…
GILLS
Fish and tadpoles are aquatic vertebrates. They possess gills for gaseous exchange. Gills of fish Fish has four gills on each side of the head. Each gill has two rows of soft gill filaments. The filaments are tiny, long…
ALIMENTARY CANAL OF PLANARIA
Planaria is a free-living, flat, slender and small worm. The digestive tract consists of a ventrally placed mouth, muscular pharynx and intestine. The pharynx can be protruded from the mouth when attacking a prey. The pharynx leads into the intestine.…
Study Guide
