In spiral cleavage,the turn of the spiral may be:

Distinguish between intracellular and extracellular digestion.

The above diagram shows the germ layers. The animals having structures shown in the figures $A$ and $B$ are respectively called:

Mesoglea is

The figures below represent diploblastic and triploblastic organization. Identify the correct labels for $P$ and $Q$.
$\quad\quad P \quad \quad Q$

What is the body cavity found between the alimentary canal and the body wall of animals called?