Which one of the following is believed to be the major event that led to the appearance of large complex animals on Earth?
A)the increase in atmospheric oxygen
B)the diversification of seaweeds in the ocean
C)the appearance of plants on land
D)the appearance of bulk flow systems

Question

Quizplus · Accepted Answer

The increase in atmospheric oxygen during the Great Oxygenation Event created a more hospitable environment for large complex animals to evolve and thrive. This increase in oxygen allowed for the development of respiration and more efficient metabolism, which were crucial for the evolution of larger and more complex organisms.

Which One of the Following Is Believed to Be the Major