What is wrong with the following set of main points for a speech about different kinds of pianos?

What is wrong with the following set of main points for a speech about different kinds of pianos? Explain the problem and then rewrite the main points to solve it. I.​Grand pianos are the largest and most expensive pianos. II.​Upright pianos take up less floor space and have poorer tone quality than grand pianos. III.​Electronic pianos are often used in jazz and rock music, while player pianos, which produce music ​​​ automatically, were popular in the late 1800s. 3.​What is wrong with the following set of main points for a speech about preventive medicine? Explain the problem and then rewrite the main points to solve it. I.​The first basic step in preventive medicine is maintaining a well-balanced diet. II.​Learning how to cope with stress is another basic step in preventive medicine. III.​The third basic step in preventive medicine is keeping a regular exercise program