Number of trophic levels are limited in ecosystem and are not more than $4$ or $5 .$ Because the energy flow decreases at successive level.

Therefore remaining energy is used in Biotic processes to maintain respiration and maintain life. If the number of trophic level are more then remaining energy decreases therefore at second trophic level cannot support in the form of energy flow. Therefore food chain remains limited upto $4$ to $5$ trophic level.

E.g.,

$\begin{array}{lllll}\text { Sunlight } & \frac{1 \% \text { is }}{\text { absorbed }} & \text { Plants } \frac{10 \% \text { is }}{\text { transformed }} & \text { deer } \frac{10 \% \text { gets }}{\text { converted }} & \text { Tiger } \\ (30,000 \mathrm{~J}) & (300 \mathrm{~J}) & (30 \mathrm{~J}) & (3 \mathrm{~J})\end{array}$