Answer:
The function of decomposers in a food web is to recycle nutrients into soil.
Explanation:
A is correct because the decomposers are able to digest the dead biomass, release nutrients from them in the soil, thus recycle the nutrients, and enrich the soil.
B is not correct because this is a function performed by the producers.
C is not correct because this is also a function that is performed by the producers, or by the primary consumers.
D is not correct because the decomposers do not compete for oxygen with the secondary consumers.
