Answer:
It would be highly unlikely to discover a food chain containing 10 links.
This is mainly due to the loss of energy that occurs with transitions through the links in the chain. Almost 90 percent of the energy obtained at one trophic level is lost when being transmitted to the other trophic level ( link in the food chain).
This means that the 10th link in the chain would get so little energy consuming the 9th level organism that it wouldn't be enough to survive.
The 2nd link gets only 10% of the initial energy absorbed by the 1st link in the chain. If the chain is 10 links long, you would lose 90% with each link, leaving next to nothing for the last few links.