Select all that apply. to increase agricultural production, the tang dynasty 1. encouraged foreign trade 2. constructed waterwheels 3. built dams to provide for irrigation 4. converted bad land into agricultural fields 5. invented new farming methods

3. built dams to provide for irrigation

4. converted bad land into agricultural fields

5. invented new farming methods

Explanation:

After the nation was united, the Tang dinasty made strong efforts to mantain it that way, and one of those was to heavily support and fund agriculture, at that time food supply was on of the most important things to keep an empire running, so they developed and constructed dams to provide irrigation, found ways to convert bad land into agricultural fields and invented new farming methods, like soaking the seeds in different compounds very planting them in order for the plantation-growth rate to be more effective, they also initiated to use insecticides and pesticides which increased considerably the harvest.

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.