Answer:
vertebrates are further classified in to subgroups on the basis of many conditions
1. on the basis of weather
warm blooded and cold blooded
2. on the basis of skeleton
exoskeleton and exoskeleton
3. on the basis of way of taking oxygen (respiratory organs.)
either through skin, gills or lungs
4. Number of chambers in heart.
5. The method of reproduction
on the basis of above criteria, vertebrates are divided in to many classes.
1) Pisces (fishes)-
- have exoskeleton
- heart is 2 chambered
- respiration through gills
2) Amphibia
- slimy skin
- heart is 3 chambered
- respiration through gill in larvas
3) Reptilia-
- exoskeleton
- heart is 3 chambered
- laying under water eggs
4) Aves (birds)-
- heart is 4 chambered
- eggs laying
5) Mammalia-
- have exoskeleton
- heart is 4 chambered
- give birth to young baby
