21.   In remote regions, the air is pure and the crops are free of poisonous insecticides.

22.   The main crop is wheat and this is grown even on the very steep slopes.

23.   Staple food crops are maize, sorghum and wheat.

24.   Land which is unfit for food crops can be used to grow crops for biogas production.

25.   The seed was defective and the resulting crop was little better than useless.

26.   Certain soils, like the Kalahari and Benin sands of Africa carry good forest, but, if cleared, only two worthwhile crops can be grown.

27.   Although biotechnologists had previously had success in breeding resistant broad-leaved crops, such as soya beans and tobacco, cereal crops have been much more difficult to modify.

28.   Initially, crops were grown which were known to have a high tolerance for metals and sulphates such as alfalfa, wheat and corn.

29.   And since the custom was revived four years ago the cider crop has never been better.

30.   The crop is a strain of cannabis or hemp that has almost no effect as a drug, and is completely legal.