Question

The first eukaryotic cells emerged during the ______.

Options

• Palaeozoic

• Cenozoic

• Mesozoic

• Proterozoic

Answer 1

The first eukaryotic cells emerged during the Proterozoic.

Explanation:

Free-living eukaryotic cell-like organisms evolved in the primitive ocean roughly 1.5 billion years ago during the Proterozoic. This era marked the transition from simple prokaryotic life to more complex eukaryotic cells that possessed a true nucleus, mitochondria, and specialized organelles, setting the stage for the evolution of multicellular life.