The answer is 20. Duplicated chromosome has two sister chromatids, identical copies of the chromosome. These two chromatids are joined at the region called centromere. Therefore, one duplicated chromosome has one centromere and two sister chromatids. If there are 20 duplicated chromosomes in a cell, there will be 20 centromeres.
The biggest airlines flying to United States: American Airlines flights to United States, Delta flights to United States, Southwest Airlines flights to United States. Regions in the USA - United States. Airlines flying to the USA - United States - by city.
South west. South west Airlines is usually a major U. S. airline plus the world's biggest low-cost service provider, headquartered in Dallas, Texas. The airline was founded in 1967 and also adopted it's current brand in 1971. The airline has nearly 46,000 employees at the time of December 2014 and also operates in excess of 3, 400 flights every day. As connected with June 5, 2011, it carries the most domestic passengers of any U. S. airline.