Explain how human activities can cause an imbalance in biogeochemical cycling and lead to problems such as cultural eutrophication and fish killing

Biogeochemcal cycling refers to the cyclic movement and turn over of the essential elements  of living matter. Due to various human activities, most of these cycles have been thrown out of balance. Alteration in biogeochemical cycle together with climate changes leads to various problems such as destruction of biodiversity, food security, eurtrophication, etc. The killing of fish in water bodies occurs, when the fish do not have enough oxygen to breath as a result of eutrophication. Eutrophication refers to the excessive richness of a body of water which result in dense plant growth that takes oxygen away from the water body. 

Ithink option a is correct because you cannot donate a different blood group than yours because it won't match.option a says betsy can donate to mark. they have the same blood group so donation can happen.