Galileo challenged the idea that objects in the heavens were perfect by .

a. proving Kepler's laws were correct
b. showing that heavy objects fall at the same rate as lighter objects
c. inventing the telescope
d. observing sunspots on the Sun and mountains on the Moon

d. observing sunspots on the Sun and mountains on the Moon

Explanation:

Galileo was an Italian Physicist and Astronomer and is regarded as the father of modern Physics.

It was previously believed that the objects in the heavens such as the sun, moon and stars were perfect and rough till he observed sunspots on the sun and mountains on the moon which indicates the surface of the moon is rough with mountains and craters.

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

the answer is b i think