Answer:
Option-C
Explanation:
The oxygen revolution refers to the increasing concentration of oxygen in the atmosphere around 2.3-2.4 billion years ago.
The studies have suggested that before the oxygen revolution the Earth's atmosphere was full of the hydrogen sulfide and methane gas in which the anoxygenic prokaryotes were evolving.
The cyanobacteria and other photosynthetic bacteria evolved the photosynthetic pigments which performed the experiment and oxygen gas was produced as a by-product.
With time this oxygen got accumulated in the atmosphere and the oceans and became one of the factors of anaerobic prokaryotic, the condition which they cannot escape. Later the oxygen producing prokaryotes evolved and formed the first eukaryotes.
Thus, the selected option is the correct answer.
Answer:
Its D- Weather is a highly complicated system that is very difficult to predict.
Explanation:
Weather has a pattern so A is not the answer and no way Meteorologists would keep information to themselves so not B and lastly it's not impossible but just very hard so C is out, which leaves D.
The ozone hole over the Antarctic has begun to heal, according to a new study, more than 30 years after its discovery. ... The stratospheric ozone layer protects Earth from the sun's harmful ultraviolet (UV-B) rays, which can cause skin cancer and cataracts in humans, and physiological damage in animals and plants.
On the other hand typical human contains app. 50 trillion cells<span>
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