Nucleus - spherical body containing many organelles, including the nucleolus. The nucleus controls many of the functions of the cell (by controlling protein synthesis) and contains DNA (in chromosomes). The nucleus is surrounded by the nuclear membrane.
These types of nerves are called "Sensory Neurons" :)
A soil can be low in ammonium and potassium ions because of increased acidity of the soil. The acidity is caused by hidrogen (H) and Al (alluminuim) ions. There few causes: acid rain, nitrate leaching, rainfall, decompositions of organic matter (leaves, corps etc) due to microorganism activity.
I would say C.nervous system because that pretty much defines all of the answer choices.
