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.
Southwest Airlines Co. (NYSE: LUV) is a major U.S. airline, the world's largest low-cost carrier, headquartered in Dallas, Texas. The airline was established in 1967 by Herb Kelleher and adopted its current name (Southwest Airlines) in 1971. The airline has more than 52,000 employees as of July 2016 and operates more than 3,900 departures a day during peak travel season. As of 2014, it carried the most domestic passengers of any U.S. airline. As of July 2016, Southwest Airlines has scheduled services to 98 destinations in the United States and seven additional countries with service to three airports in Cuba expected to begin later this year, subject to governmental approvals.