Final answer:
The significant legislation passed by George W. Bush is the No Child Left Behind Act (NCLB), signed into law in 2002, which mandates testing for students and conditions federal funding on school performance.
Step-by-step explanation:
The important legislation passed by President George W. Bush is the No Child Left Behind Act (NCLB). This Act was signed into law in January 2002, following Bush's campaign promise of "compassionate conservatism" and an education reform to close the achievement gap between disadvantaged groups and their peers. The NCLB Act requires states to administer tests to students in certain grades, and these test results determine eligibility for federal funding. Schools that fail to meet the standards could face reductions in funding, changes in curriculum, and other significant consequences. The legislation aimed to improve educational outcomes by holding schools accountable for student performance.