8   3 Peat bogs are formed over millions of years from the remains of plants and animals. Waterlogging and acidic conditions prevent the decomposition of plants and animals in peat bogs. The photograph shows peat being cut from a peat bog. (Source: © Reimar/Shutterstock) (a) (i) State how the age of the layers in a peat bog can be determined. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why the conditions in peat bogs prevent decomposition. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 9   (b) In the 1980s, there was a scheme to plant trees in areas of peat bog. This dries out the bog and allows it to decompose, releasing the carbon dioxide locked in the peat bog. Conservationists are cutting down trees and raising the water level to recreate the peat bog. It is estimated that the peat bogs will recover in 15 years. The photograph shows sphagnum moss that grows on the surface of peat bogs and helps their formation. (Source: © Jan Holm/Shutterstock) Devise a procedure to measure the rate of recovery of the peat bog. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 3 = 8 marks)