Earth<span> can be divided into three main </span>layers<span>: the core, the mantle and the crust
Your answer would be, Core.
(Could also be called inner core)
Think of it as a watermelon, you have the crust, which is the green part, the mantle which is the whitish green part and the red which is the core.
Hope this helps.
In case you didn't get any of that, the answer is Core</span>
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!
That would be called a source or head water
