Question

Read the following characteristic features
(a) Umbrella shaped body
(b) Free swimming mode of life
(c) Cnidoblasts for defence, capture of prey etc,
(d) Digestion is by both extracellular and intracellular modes
The above features are noticed in​

Answer 1

Hydrozoa, Cnidarians exhibit two basic body forms called polyp and medusa. The former is a sessile and cylindrical form like Hydra, Adamsia, etc. whereas, the latter is umbrella-shaped and free - swimming like Aurelia or jellyfish. These Cnidarians, which exist in both forms exhibit alternation of generation (Metagenesis), i.e., polyps produce medusae asexually and medusae form the polyps sexually (e.g., Obelia).