The four sentences (labelled 1, 2, 3, 4) 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. Living things—animals and plants—typically exhibit correlational structure.

2. Adaptive behaviour depends on cognitive economy, treating objects as equivalent.

3. The information we receive from our senses, from the world, typically has structure and order, and is not arbitrary.

4. To categorize an object means to consider it equivalent to other things in that category, and different—along some salient dimension—from things that are not.