24) In the 13th century, ....laid the foundations of modern science, by insisting on the experimental method, and discovered the uses of gunpowder and the magnifying lens.

25) Nicholas Copernicus of ....revolutionized the thought of mankind by proving that the earth moves round the sun.

26) ....of Poland revolutionized the thought of mankind by proving that the earth moves round the sun.

27) Galileo was an .. astronomer

28) John Kepler was an .... astronomer