A more thorough explanation:

The No Child Left Behind Act of 2001 was a law created by President George W. Bush to improve education in the United States. The law required schools to give standardized tests to students in grades 3-8 in reading and math. The results of these tests were used to measure how well schools were doing and to identify areas where they needed to improve.

The law also required states to make sure that all teachers were qualified to teach their subjects. Schools that did not meet certain standards were given consequences, such as allowing students to transfer to better schools or offering free tutoring.

For example, if a school had a lot of students who were not doing well on the standardized tests, the school might have to offer free tutoring to those students. This would help them improve their scores and meet the standards set by the law.

In 2012, President Barack Obama made changes to the law to give states more flexibility in how they met the standards. This allowed states to come up with their own plans for improving education, as long as they met certain requirements.

Overall, the No Child Left Behind Act of 2001 was an important law that helped to improve education in the United States by setting standards and holding schools accountable for meeting them.