Answer:
2 unit
Explanation:
According to the 10% law, the transfer of biomass energy from one higher trophic level to lower trophic level is only 10%.
Primary(Producer)→Primary consumers→secondary consumers→tertiary consumers.
that is 2000→200→20→2
note: only 10% of the total biomass is received by the next trophic level.
therefore tertiary consumers will receive 2 units of biomass.