26. A? ?Most forms of steel abruptly become brittle

27. J? ?... that resists fractures at much lower temperatures

28. B? ?without the need for expensive additives

29. E? ? ?providing a lifeline for the besieged British

30. I? ?the ships cracked in the icy north Atlantic

31. N? ?So scientists have strived to find a solution

32. C? ?a more physical approach

33. G? ?that is comparable to that of..

34. H? ?the number of components needed in a construction. Job

35. K? ? ?by replacing solid supports with hollow tubes