What are ten facts about the Precambrian era?

1. The Precambrian is the earliest part of Earth's history, set before the current Phanerozoic Eon.

2.The Precambrian was originally defined as the era that predated the emergence of life in the Cambrian Period.

3. During the Precambrian era the earth started cooling and the outer edge of the planet solidified from molten lava to a solid crust. Water rained from the atmosphere and created oceans.

4. It is The first and longest subdivision of time for the earth.

5.  The earth took form about 4.5 billion years ago. For the first 4 billion years of that time, the Earth was growing and changing.

6. he only multi-cellular life forms at the end of the Precambrian were in the oceans and included some groups that have survived until the present: jellyfishes and segmented worms.

7. The discovery of 3.85-billion-year-old marine sediments and pillow lavas in Greenland indicates the existence of liquid water and implies a surface temperature above 0 °C (32 °F) during the early part of Precambrian time.

8. The Precambrian encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4 billion to about 541 million years ago.

9. Precambrian rocks on most continents have revealed that additional primitive life-forms existed approximately 3.5 billion years ago.

10. The earliest evidence for the advent of life includes Precambrian microfossils that resemble algae, cysts of flagellates, tubes interpreted to be the remains of filamentous organisms, and stromatolites (sheetlike mats precipitated by communities of microorganisms).

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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