Ans: Jellyfish are been divided into 4 different groups, they are as followsScyphozoa- This is the most common form which is formed abundantly in the sea. There are around 200 species which are found for this type. This type of jellyfish spends most of its lifespan in Medusa state, these are big and colourful. Hydrozoa- These are not found so easily in the sea. IT stays a very little time in the Medusa state, but the Polyp form results in the formation of a large number of colonies. Cubozoa- They are commonly known as the box jellyfish due to their bells resembling the box. There are some species of this jellyfish which are very venomous. These species have complex retina and eyes with a well developed nervous system compared to others. These types of jellyfish exhibit elaborate courtship behaviour.Sturozoa- These are usually found attached to the rocks or seaweeds, rather than floating on the water. They're mostly found in the cold water places and usually look like a trumpet.