The answer to that is the Sahara desert.
The correct answer is (D): The tilt of the Earth on its axis changes during the year.
Earth revolves around the Sun as it spins on its axis of the rotation once a day. While the Earth orbits the Sun, the tilt of Earth's axis stays lined up with the North Star resulting to the North Pole tilting towards the Sun. The Northern Hemisphere is normally tilted toward the sun on the summer solstice while the southern hemisphere is tilted toward the sun on the winter solstice. Northern Hemisphere hence expects a change in days length where the days change from short days in the winter to long days around the summer solstice on June 21st.
The law of supply<span> is a </span>law<span> that states that, all other factors being equal, as the price of a good or service increases, the quantity of goods or services that suppliers offer will increase, etc.</span>
The correct answer is - the heliocentric system.
By using the telescope, Galileo Galilei managed to observe the movements of the Sun, Moon, the planets in the Solar System, and he was mapping their movements on the sky, and also he was comparing their movements to the Earth's position. With this, he managed to notice that insted of the popular belief that the Sun, Moon, and the other planets are moving around the Earth, that it is actually the opposite of it, and that the Sun was the center of our Solar System, and that all the planets and moons were orbiting around it, while the only object that hold its position as it was initially thought was the Moon, because it orbits around our planet. So Galileo contributed to the theory of the heliocentric system.