A:air
because the flag would on blow if it had some kind of wind
X is mathematically an unknown.
I believe it would be A.) The creation of atomic nuclei!
Answer: Friction
Explanation: Sir Isaac Newton, a soccer ball on the grass will stay where it is unless acted on by a force.
---- *Well, since there is really no specific ecosystem that was asked about in the question, I will just list some common and basic abiotic factors found throughout most ecosystems (maybe you can match this with the ecosystem you are talking about).
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Abiotic factors: nonliving parts of an ecosystem
Some abiotic factors include: ROCKS, SOIL, AIR, SUN, WATER, ETC.