(A)

No. 13

1 When each of the crops is planted is important.

2 They only grow in a small region of North America.

3 They have difficulty competing with weeds.

4 There needs to be space between the plants.

No. 14

1 Use more-modern growing techniques.

2 Find new plants that can be grown in the desert.

3 Teach others how to grow the Three Sisters.

4 Recover forgotten growing methods.