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.
warm front
// answer was short so added this text //
It is much darker 1000 meters deep and photosynthesis most likely can't occur, the fishes there also have different abilities than the ones higher up in order to survive, also it is probably a harder to swim because of the increased pressure
If you mean organelles then chloroplast
