[Campbell Biology P.574] According to the "Study Tip" timeline example, what is the earliest... | Practice Question

According to the "Study Tip" timeline example, what is the earliest event shown, and what was a key characteristic of the earliest life forms on Earth?

  • A: Oxygen revolution; all early cells were eukaryotes.
  • B: First unicellular organisms; all early cells were prokaryotes.
  • C: Origin of multicellular organisms; life on Earth began 3.5 bya.
  • D: Colonization of land by large eukaryotes; early cells were photosynthetic.

Explanation

The timeline under "Study Tip" explicitly shows "First unicellular organisms Life on Earth begins; all early cells are prokaryotes " as the earliest event.