How are igneous rocks formed?
Due to the heat within the Earth, rocks are melt. The melted rocks(magma) have a lower density than the surroundings and they come up to the surface through fissures or volcanoes. The lava that reached the surface now cools down due to the lower temperature of the surface and solidify to form rocks. These are igneous rocks.
What is El Nino?
In one sentence, El Nino is the seasonal reversal of the cold Peruvian current. In normal conditions, the waters in Australia are warmer than that in South America. So, the air above the waters is also warmer, which rises and travels towards the colder South America. Australia gets a lot of rain, while South America is dry. This is the Walker circulation. During El Nino, the difference in temperature in both the regions is lower, such that the circulation breaks in the middle of the Pacific and hence the mid-Pacific gets a lot of rain, while Australia and South America are dry.
How did the Solar System form?
The Sun was formed 4.5 billion years ago by the collapse of a hydrogen molecular cloud. During the formation of the Sun, 99% of the molecular cloud formed the Sun, while the rest existed as a protoplanetary disk around the Sun. On cooling and accumulation of materials in the disk over time, the planets were formed. This is how the Solar system formed