Was the astronomer who deduced that all the planets orbit the sun such that (i) their orbits are elliptical. (ii) they sweep out equal areas in equal times. (iii) the square of their periods is proportional to the cube of their mean orbital radii.

Johannes Kepler

Explanation: Johannes Kepler (Weil der stadt, December 27th, 1571 - Regensburg, November 15th, 1630), a key figure in the scientific revolution, was a German astronomer and mathematician; known primarily for his laws on the movement of planets in their orbit around the sun. He was a collaborator of Tycho Brahe, whom he replaced as imperial mathematician of Rudolph II.

in 1989, tiananmen square in beijing was the site of china’s main industries. china’s government headquarters. -pro-democracy demonstrations. (second choice)

the correct answer option is: weapons.

explanation:

tensions rose as the two opposing superpowers competed for 'weapons'.

referring to the cold war (1945-1991), the two superpowers, usa and ussr, experienced a phase of struggle and conflict with each other. these two superpowers considered each other as a threat to their survival and thus opted for policies to strengthen their positions.

the two superpowers never went to war with each other directly but competed for weapons to preserve their positions.