A food web:-

Question

$\begin{array}{1 1}(a)\;\text{Increases variety of food,at each trophic level}\\(b)\;\text{Balanced interrelationship among organisms}\\(c)\;\text{Decreases variety,but increases qty of food at each trophic level}\\(d)\;\text{Increases variety,but decreases qty of food at each trophic level}\end{array}$