(a)[5]
Explain how the protein in the cattle manure is changed into the ions that plants can take up.
(b(i))[1]
Suggest the advantage to farmers of snap bean plants having a large number of root nodules.
(b(ii))[3]
Calculate the percentage increase in the average number of root nodules per plant when snap bean plants were grown with a large quantity of cattle manure (field 3) compared with no cattle manure (field 4). Give your answer to two significant figures.
(b(iii))[4]
Describe how eutrophication in streams and rivers can result in the death of fish.