Question

why are smaller food chain better

Answer 1

Energy is lost at every trophic level to the surroundings. By going to the next trophic level, more and more energy is lost. Therefore, it is better that food chains are short. A shorter food chain means more energy available to the final consumer because less energy is lost to the surroundings. Therefore, a shorter food chain is more efficient than a longer food chain.

Answer 2

Due to the food chain,the energy flows through different living organisms in our environment.

And in every single transfer of energy ,the total amount of transferred energy decreases from it's previous transfer.

That's why the last living organism in a food chain gets the lowest amount of transferred energy.

But a short food chain is beneficial for the last living organism of the food chain because the length of a food chain is inversely proportional to the amount of energy obtained by the last living organism of that food chain.