The five sentences (labelled 1, 2, 3, 4 and 5) given below, when properly sequenced would yield a coherent paragraph. Decide on the proper sequence of the order of the sentences and key in the sequence of the four numbers as your answer.

1. Before plants can take life from atmosphere, nitrogen must undergo transformations similar to ones that food undergoes in our digestive machinery.

2. In its aerial form nitrogen is insoluble, unusable and is in need of transformation.

3. Lightning starts the series of chemical reactions that need to happen to nitrogen, ultimately helping it nourish our earth.

4. Nitrogen — an essential food for plants — is an abundant resource, with about 22 million tons of it floating over each square mile of earth.

5. One of the most dramatic examples in nature of ill wind that blows goodness is lightning.