- George Wofan ( Planetesimal Hypothesis) : The earth along with other planets and satellites were formed when a comet moving around the universe stroke the sun many years ago.
- Kant and Laplace(Nebular Hypothesis): When a gaseous mass revolving the sky began to cooland shrinked resulting many small masses come out forcefully and began to round the central mass, the sun where as other revolving bodies formed planets and satellites.
- Jeans and Jeffery(Tidal Hypothesis): Tidal effect was occurred in the sun when a big star was passing nearby to it and later the tidal matter fragmented and cooled to form planets and satellites etc and became the solar system.
Fossils: The remains of plants and animals which were buried under the earth before millions of years are called fossils.
Formation: The dead bodies of living beings are deposited at the bottom of the sea and covered with materials like sand, mud etc. The soft part of dead bodies of living beings get decayed while the hard part of dead bodies of them remains as fossils between the layers of sedimentary rocks get preserved in the rocks.
Formation of coal: Millions of years ago the dense forests (trees, fern plants) in the marshy land were buried below the earth’s surface due to the geological movement like earthquake. The buried trees are covered with more and more sediments along with water. They are pressed due to which the temperature also increases. The combined action of high pressure and temperature causes decomposition of organic matters present in trees into carbon. The carbon thus formed is pressed more and more and finally coal is formed after millions of years.
Formation of mineral oil: Mineral oil is formed from plants and animals. The dead bodies of plants and animals are buried under the ground. These organisms happen to lie under the ground because of different types of natural disasters as well. In the course of time, many materials get deposited over the buried plants and animals and they are greatly pressed. Soft parts decay and hard parts are further squeezed. They decomposed due to the combined effect of high pressure and temperature. As a result hydrocarbons are formed. Hydrocarbons remain in liquid state due to high pressure and get collected between the rocks. In fact, it is a crude oil or mineral oil. Mineral oil is formed in the areas nearby the seas and oceans. It takes millions of years for the formation of mineral oil.
1. Human beings have not seen a real dinosaur.
Ans- The evolution, development and disappearance of dinosaur were already happened in Mesozoic era but the human beings were evolved in Pliocene period of Cenozoic era. So, human beings have not seen a real dinosaur.
2. Mesozoic era is called the time of reptile s(or golden age of reptiles)
Mesozoic era is also called as age creepers.
Ans- Mesozoic era is called the time of reptiles because there was the dominance of various types of large reptiles like dinosaurs, turtles etc. on the land and marine water in this era.
3. Living beings are evolved millions of years after earth was created.
Ans- Living beings are evolved millions of years after earth was created because the earth was very hot and there was not the suitable temperature, climate and atmosphere for the evolution and survival of living beings. So there was no life at the time of the evolution of the earth.
4. Coal is called fossil fuel.
Ans- Coal is called fossil fuel because it is non-renewable source of energy ans is formed from the dead bodies of plants and animals that are preserved in sedimentary rocks.
5. Fossils are found only in sedimentary rocks.
Ans- Fossils are the relics of dead plants and animals which were buried under the earth before millions of years. Due to the sedimentation of sand and mud the fossils are formed under high pressure. So the fossils are found only in sedimentary rocks.
6. Natural gas are found mostly on the top of mineral oil in nature.
Ans: Natural oil and mineral oil are formed from the fossils of plants and animals. When the plants and animals are decomposed by the combined effects of high temperature and pressure, hydrocarbons are formed. The hydrocarbons in liquid form constitute mineral oil and those which are in gaseous state form natural gases. The density of gase is less than that of liquid. So natural gases are mostly found on the top of mineral oil in nature.