Question

ensuring that all cells of an individual arise from a single cell prevents the... cells from outside becoming incorporated into a new body. cells in your body from competing with other cells. rewatch

Explanation:

When all cells of an individual arise from a single - cell, it ensures that the cells are genetically related and part of the same organism. This mechanism prevents foreign cells from being incorporated into the new body. Foreign cells could potentially be pathogens or cells from another organism that would disrupt the normal functioning of the individual. Cells in the body do compete with each other in normal physiological processes like cell - cell signaling and resource acquisition, and this single - cell origin is not related to preventing such normal competition among body cells.

Answer:

cells from outside becoming incorporated into a new body.