"tryptophan self-controls its synthesis." justify this statement.

Tryptophan self-controls its synthesis. If we have a large amount of tryptophan in the sense that it exceeds, tryptophan would act as a co-repressor which prevents synthesis of more enzymes for its production. Hope this answers the question.

The hawk receives 0.1% energy from the caterpillar although the caterpillar gets eaten by another bird smaller than the hawk first