Page 07 12. Which row in the table below identifies a stage of aerobic respiration, its site and an event which occurs during that stage? Stage Site Event A electron transfer chain inner mitochondrial membrane carbon dioxide is released B electron transfer chain matrix of mitochondrion hydrogen ions combine with oxygen C citric acid cycle inner mitochondrial membrane hydrogen ions combine with oxygen D citric acid cycle matrix of mitochondrion carbon dioxide is released 13. A field trial was set up to investigate the effect of phosphate fertiliser on the yield of the potato cultivar Maris Piper. Potatoes were planted in 5 plots, each of which received a different level of phosphate fertiliser. When they were harvested the yield from each plot was recorded. A list of suggested improvements to this field trial is shown below. 1 Apply equal volumes of water to each plot. 2 Grow the same number of potato plants in each plot. 3 Use 10 plots at each phosphate fertiliser level. 4 Plant different potato cultivars in each plot. Which of the suggestions would improve the validity of the results? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4 [Turn over