The Permian period ended and then rapid speciation occurred as new animal and plant forms evolved. The most likely explanation for this is _____.
I) adaptive radiation
II) ecological opportunity
III) lack of competition
IV) morphological innovation
A) just one of the above
B) two of the above
C) three of the above
D) all of the above

The Permian period refers to the last period of the Paleozoic era, which started about 300 million years back and ended by about 250 million years back. The Permian period was ended by the occurrence of a catastrophic mass extinction event, commonly known as the Permian-Triassic (P-T) boundary.

Soon after this eruption, there occurred rapid evolution of plants and animal species, and this was possible because of the following reasons-

Adaptive radiation- This type of evolutionary process refers to the condition when numerous species are created from one single ancestor. It takes place when there occur sudden changes in the environmental conditions, favorable for their growth and expansion of organisms.

Ecological opportunity- It is directly associated with the adaptive radiation type of evolutionary process. When changes in the environmental condition occur, it allows the organisms to adjust to the new environment and eventually gets multiplied.

Lack of competition- By the end of Permian, about 75% of all the living species on earth were wiped out. So, the new species that appeared had no competition and so they were able to grow in large numbers over a specific period of time.

Thus, the correct answer is option (C)- three of the above.