Answer:
The correct answer would be - complex eyes evolved in the gradual steps, each of which was fully functional and adaptive in improving visual acuity.
Explanation:
The natural selection of the complex traits such as the vertebrate eye (complex eye) are seems to be problematic, many biologist think that the complex eyes evolution is take place in gradual steps and each step of this evolution was adaptive and functional in improving the visual acuity.
The steps that were involved are like light sensitivity patch, a deepening hole or pit that help in sharp vision and many other random evolution steps.
Thus, the correct answer is- complex eyes evolved in the gradual steps, each step of this evolution was fully functional and adaptive that helps in improving visual acuity.
