The conversion efficiency from herbivores to carnivores is the least efficient of the tropic levels with an average conversion of
a.
1 – 5%
b.
0.5 – 1%
c.
7 – 12%
d.
15 – 20%

The correct answer is option a.

"1 – 5%".

Explanation:

The conversion efficiency, also known as trophic assimilation efficiency, refers to how much energy is retained in the consumer in comparison with the amount of energy stored in the producer or the organism in the previous trophic level. The higher the trophic level the higher conversion efficiency. Therefore, the conversion efficiency from herbivores to carnivores is very low, because carnivores are at the lowest trophic levels in the food chain. The conversion efficiency at this level reaches barely 5% in some cases. This is the reason why there are very few tertiary carnivores in comparison to the number of plants on Earth.