(N/A) The number of trophic levels in an ecosystem is limited and generally does not exceed $4$ or $5$. This is primarily because energy flow decreases significantly at each successive trophic level.
According to the $10 \%$ law of energy transfer,only about $10 \%$ of the energy available at one trophic level is transferred to the next level. The remaining energy is utilized by organisms for biotic processes,such as respiration,growth,and reproduction,or is lost as heat.
If the number of trophic levels were higher,the amount of energy remaining at the higher levels would be insufficient to support the metabolic requirements of the organisms. Therefore,food chains are naturally restricted to $4$ to $5$ trophic levels.
Example:
$\text{Sunlight } (30,000 \text{ J}) \xrightarrow{1\% \text{ absorbed}} \text{Plants } (300 \text{ J}) \xrightarrow{10\% \text{ transferred}} \text{Deer } (30 \text{ J}) \xrightarrow{10\% \text{ transferred}} \text{Tiger } (3 \text{ J})$.