The book $Systema \text{ } Naturae$ was written by:

The skeleton is made entirely of cartilage in:

Give the points of differences between non-chordates and chordates.

Organisms without a nucleus and cell organelles belong to:
$(i)$ Fungi
$(ii)$ Protista
$(iii)$ Cyanobacteria
$(iv)$ Archaebacteria

In which group of animals is the coelom filled with blood?

An animal is dorsoventrally flattened,has three embryonic germ layers,and is acoelomate. Which phylum does it belong to? What are they commonly called? Give one example.