Identify the one underlined word or phrase that must be changed in order for the sentence to be grammatically correct. 1. According to the economic laws, the greater the demand, the high the price. 2. The curricula of American public schools are set in individual states; they do not determine by the federal government. 3. Aeronomy is the study of the Earth’s upper atmosphere, which includes their composition, temperature, density, and chemical reactions. 4. Psychology Today is interesting, informative, and it is easy to read. 5. Alloys of gold and gold and copper have been widely using in various types of coins. 6. Aristotle believed that everything in the universe were composed of four basic elements: earth, water, air and fire. 7. One type of Australian frog lays up to 25 eggs at a time and then swallows they for protection. 8. Every human typically have three twenty-three pairs of chromosomes in most cells. 9. A quantitative analysis, using both the computer and quantitative techniques, are used to optimize financial decisions. 10. To enter the FBI National Academy, an application must be between the ages of twenty�three and thirty-four. 11. The flag of original first colonies may or may not have been made by Betsy Ross during the Revolution. 12. The most common form of treatment it is mass inoculation and chlorination of water sources. 13. Farmers look forward to have participated in the county fairs every summer. 14. When a body enters the Earth’s atmosphere, it travels in very rapid manner. 15. Gunpowder, in some ways the most effective of all the explosive materials, were a mixture of potassium nitrate, charcoal, and sulfur.