The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
The answer to your question is Starch
Answer:
Roots---xylem vessel-- upper parts of plant.
Explanation:
The plant absorb water from hairs present on the roots and taken this water to the xylem vessel that is responsible for transporting water to all parts of the plant body. Water enters in the root through a process is called osmosis until it reached to the xylem vessel. Osmosis is a movement of molecules through a semi-permeable membrane into a region of higher solute concentration in order to equalize the solute concentration.
