Multicellular organisms require a lot of energy and resources to survive.
Unicellular organisms, on the other hand, require just the basic necessities. On top of that, unicellular organisms don't require a long time to reproduce as multicellular organisms do.
Thus, multicellular organisms are at a disadvantage because they require more energy, sources, and essentially time.
Hope this helps!
The correct answer is option b, that is, the addition of carbon dioxide to the atmosphere.
If the concentration of carbon dioxide upsurges in the atmosphere due to the enhanced rate of outgassing, there will be a constant elevation in the global temperature. The elevating temperature and more dissolved carbon dioxide will result in enhanced weathering of crystal rocks as a consequence of faster rate of reactions and greater acidity.
<span>Stem cells. There are two types of stem cells: adult stem cells - these are unspecialised cells that can develop into many (but not all) types of cells. Embryonic stem cells - these are unspecialised cells that can develop into any type of cell. And that's all! ;)
Hope this is useful !!!^_~!!!</span>
