True coelom appeared first in the course of evolution in
Aschelminthes
Chordata
Echinodermata
Annelida
D.
Annelida
Phylum Annelida shows evidence for first true coelomates. Species belonging to annelida eg. Nereis, hirudinaria etc. Show presence of all three germ layers viz. Ectoderm, Endoderm and Mesoderm. The cavity (coelom) is lined by the cells of Mesoderm. Annelids are schizocoelomates. Mesoderm splits and forms the schizocoelom. In schizocoelomates the opening of the embryonic gut first develops into mouth and later forms the anus.
Which one feature is common to leech, cockroach and scorpion
Nephridia
Cephalisation
Ventral nerve cord
Antenna
Which of the following is not found in vertebrates
Bilateral symmetry
Gill opening
Body scales
Cnidoblasts
Tube-within-a-tube body plan is shown by
coelenterates
platyhelminthes
aschelminthes (nemathelminthes)
porifers
Assertion : The duck-billed Platypus and the spiny ant-eater, both are egg-laying animals yet they are grouped under mammals.
Reason : Both of them have seven cervical vertebrae and 12 pairs of cranial nerves.
If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false
