The would most likely have to compete for their food and space.
Answer -
T-Cell - White blood cell = Fight off Intruders in the body
B-Cell - Macrophages = Creates Antibodies against antigen.
Cell Differentiate - Stem Cells = My favorite cell of all time in animal because they can turn into almost any cell like neural, signaling, euthyroid. Etc
All parts in the flowchart contribute to the breakdown of glucose and cell respiration. Without every part in the flowchart, we wouldn't be able to be alive right now. Each part in the flowchart work together. Hope this helps!
When the two atoms are split
The answer to this question would be: rapid impulse transmission.
By having organ near the head, the brain can process the information faster because the length of the nerve that carries the impulse from organ would be much shorter. The nerve also at lower risk of damage since it was shorter.
But it makes the head very important and damage to the head can cause much more problem than any part of the body.