Question

The body of sponges does not possess tissue level of organisation, though it is made up of thousands of cells. Comment on it.

Answer 1

The body of sponges does not posses lev. of org. though it is made up of thousands of cells bcz nerve cells which serves as connection
b/w the cells are absent. as there is no connection tissues are not formed.

proneurons r present in place of neurons

Answer 2

In Phylum porifera or sponges the cells are usually loosely organized into cellular organization but are not organized into tissue levels or organs. Due to their simplicity of sponge structure there are colonies of independent cells. These cells are specialized for particular functions, referred to as division of labour. The main three types of cells are:

i. Pinacocytes: outer surface of sponges

ii. Mesenchyme cells: jelly like middle layer

iii. Choanocytes: inner lining