Which of the following is not a reason for the lack of a fossil record from the precambrian time? a. the single-celled organisms that existed during that time did not leave easily identifiable fossils. b. like the rocks of the phanerozoic eon, precambrian rocks contain many visible signs of complex life forms. c. multi-celled organisms evolved in the oceans during the latest years of the precambrian time. d. precambrian rock has been eroded or metamorphosed over billions of years, and very little of it remains at the surface.

The right answer is B

The development towards 1.4 Ga of eukaryotes, aerobic organisms such as unicellular algae, will be decisive for the oxygenation of the Earth's atmosphere.

The first multicellular organism is a red alga dating back to 1200 Ma during the Mesoproterozoic era (part of Precambrians). Various forms of life with soft bodies dated between 600 and 541 Ma constitute what is called the Vendian fauna, that is to say the fauna of the Ediacarien.

The appearance of a great diversity of small shelly fauna from 541 Ma will mark what is called the Cambrian explosion.

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.