The answer would be b) push factors
Formation. Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed, possibly due to the shockwave of a nearby exploding star, called a supernova. When this dust cloud collapsed, it formed a solar nebula—a spinning, swirling disk of material. Approximately 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula. With the rise of the sun, the remaining material began to clump together. Part of Hall of the Universe. The Sun and the planets formed together, 4.6 billion years ago, from a cloud of gas and dust called the solar nebula. A shock wave from a nearby supernova explosion probably initiated the collapse of the solar nebula. ... In a similar manner, moons formed orbiting the gas giant planets. Hope this helps!
Climate refers to weather conditions for a region over a period of time.
In this circumstance one should revise the hypothesis and develop a new experiment to test it.An example could be the theory of Agraham Gottloeb Werner that all rocks were precipitated from water including not just sedimentary rocks but also volcanic, plutonic and metamorphic rocks. The more the earth was studied, especially by James Hutton in Scotland, the more it became obvious that granites for example were deposited in a molten state, thus disproving that hypothesis or theory.