Explain how animals in vertebrata are classified in to further subgroups.

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)-

2) Amphibia

3) Reptilia-

4) Aves (birds)-

5) Mammalia-

hi~~

i would say that hybridization occurs frequently in nature, because there are many types of hybrids that have occurred naturally, such as the mule (male donkey + female horse)

the index of refraction of the second medium is higher. i just took the test trust me !