Which of the following was probably the least important factor in bringing about the cambrian explosion?

a. the emergence of predator-prey relationships
b. an increase in the concentration of atmospheric oxygen
c. the movement of animals onto land
d. the origin of hox genes

The correct option is C.

Explanation:

The Cambrian explosion refers to a period in the history of the world when there was rapid emergence of different phyla of animals. Scientists believed that this period was brought about by an increase in the concentration of atmospheric oxygen. The period occurred about 540 million years ago and it lasted for 53 millions years and it was a significant period because. of the evolutionary changes that it brought to the world. During the Cambrian period, the predator -  prey relationship emerge as s result of the different types of animals that exist during the period.                                                                                                                                                                                                                                                                                                                                        

it would lead to upper respiratory infections and pneumonia.