Which statement is true about stromatolites?

Question

They are layered mounds of deposits made by Precambrian algae.

Ancient eukaryotes are collectively called stromatolites.

All rocks from Precambrian time are referred to as stromatolites.

They are tiny plants that survived through Precambrian time.

Answer 1

The true statement about stromatolites is:

They are layered mounds of deposits made by Precambrian algae.

Stromatolites are formations created by the activity of microorganisms, primarily cyanobacteria, which are photosynthetic bacteria. These deposits consist of layers of organic and inorganic materials and are some of the oldest evidence of life on Earth, dating back to the Precambrian era.