Answer:
30 units of energy will be available to primary predators.
Step-by-step explanation:
Using 10 % law i.e at each step 10 % of energy is transferred to the next trophic level at the rest of either consumed or lost to environment..
so plants have = 3000 units
herbivores = 10% of 3000 = 10/100 × 3000
= 300 units
so primary predators will have = 10% of 300
= 10/100 × 300 = 30 units