7: symbiotic relationship
8: mutualism
9: commensalism
Aauguccagg because t becomes a, a becomes u, c becomes g, and g becomes c.
Answer:
O.
Explanation:
There are different types of soils and it is made up of different layers or horizon such as A, B, C, O, R and E. Together all the horizons forming soil profile. Each horizon containing different soil types.
O horizon: Known as top layer of the soil which contains layer of organic matter which is about two inches thick, and made up of humus such as decomposing leaves, dark-colored, carbon rich matter, twigs and microbial biomass which is mixed with small grained minerals for the formation of aggregate structures.
