Biology Evolution UHS 2023
PMDC Verified Question 15 of 47
According to evolutionary studies, prokaryotes may have arisen around:
A
2.5 billion years ago
B
3.5 billion years ago
C
4.5 billion years ago
D
5.5 billion years ago
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: 3.5 billion years ago
Concept:

The timeline of life on Earth is established through the radiometric dating of ancient rocks and fossils.

Solution:

  • Earth is estimated to be about 4.5 to 4.6 billion years old.
  • The oldest known definitive fossils of living organisms (stromatolites formed by ancient cyanobacteria/prokaryotes) date back to approximately 3.5 billion years ago.
  • These simple single-celled organisms dominated the Earth for billions of years before the first eukaryotes appeared.


Why other options are incorrect:

  • 4.5 billion: Roughly the formation of Earth, too early for life.
  • 2.5 billion: Eukaryotes began emerging around roughly this era, but prokaryotes are much older.
  • 5.5 billion: Older than the solar system itself.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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