Galileo's observational contributionsgalileo galilei was the first scientist to perform experiments in order to test his ideas. he was also the first astronomer to systematically observe the skies with a telescope. galileo made four key observations that challenged the widely accepted philosophical beliefs on which the geocentric model was based, thus providing support for the heliocentric model. from the following list of observations, which are the key observations made by galileo that challenged widespread philosophical beliefs about the solar system? check all that apply.- jupiter has orbiting moons.- venus is only seen in a crescent phase.- uranus has a ring system.- neptune has orbiting moons.- the moon has a smooth, featureless surface.- the sun has sunspots and rotates on its axis.- the moon has mountains, valleys, and craters.- venus goes through a full set of phases.

Explanation:

In 1609 Galileo built a telescope, with which he observed mountains and craters on the Moon, discovered Jupiter’s major satellites and the next year he published these discoveries in his book The Sidereal Messenger.

In addition, Galileo observed that Venus presented phases (such as those of the moon) together with a variation in size; observations that are only compatible with the fact that Venus rotates around the Sun and not around Earth. This is because Venus presented its smaller size when it was in full phase and the largest size when it was in the new one, when it is between the Sun and the Earth.  

On the other hand, although Galileo was not the first to observe sunspots, he gave the correct explanation of their existence, which supported the idea that planets revolve around the Sun.

These observations and discoveries were presented by Galileo to the Catholic Church (which supported the geocentric theory at that time) as a proof that completely refuted Ptolemy's geocentric system and affirmed Copernicus' heliocentric theory.

answer: option c. i.e. electric current flowing “downhill” from the negative electrode to the positive electrode in a battery

explanation:

the water analogy to the circuits define the pipes (water flows) to the electric current. now, we know that the electric current flows from the positive terminal to the circuit (as shown in the diagram attached).

hence, option c is the correct answer.

none, its a machine