Which of these observations of galileo refuted ptolemy's epicycles? the craters on the moon the rotation of sunspots across the sun's surface the revolution of jupiter's moons around it the complete cycle of venus' phases the visibility of many more stars with the telescope?

The answer is : the complete cycle of venus' phases. This is the observation of Galileo that refuted ptolemy's epicycles. . Using his telescope, Galileo found that Venus went through phases, just like our Moon. But, the nature of these phases could only be explained by Venus going around the Sun, not the Earth.

a, c, d, e are all applying about success strategies.

iron would move it is magnetic there is a mag field around the current in the wire