All cells have a cell membrane, one or more DNA chromosome(s), and cytoplasm.
1 No curveballs before age 14. 2  8-10 years old 52 pitches per game and no more than 2 games pitching per week 11-12 years old 68 pitches per game and no more than 2 games per week.3  Seek good pitching mechanics coaching and work on developing good balance trunk and lower extremity strength. 8-10 years old 52 pitches per game and no more than 2 games pitching per week 11-12 years old 68 pitches per game and no more than 2 games per week.
A close-up of a shot put on the throwing field. Photo Credit cherrus/iStock/Getty Images. Shot putters come in all sizes and shapes. Eight-year-old girls and 80-year-old men can participate in the shot put, but they won't all throw the same weight. Based on an athlete's sex and age, the rules for U.S. competition allow eight weights of shots.