why do trees lose their leaves

Trees lose their leaves seasonally a especially during Autumn, and to the shedding of other plant structures such as petals after flowering or fruit when ripe. 

material used to make cement

Gypsum is also used to make the cement set more slowly, The main ones are Limestone and Shale. 

what is the raw material used to make petrol

Petroleum, from Medieval Latin petroleum, from Latin petra rocklatin: oleum oil is a naturally occurring, yellow-to-black liquid found in geologic formations beneath the Earth's surface, which is commonly refined into various types of fuels. It consists of hydrocarbons of various molecular weights and other liquid organic compounds. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. Afossil fuel, petroleum is formed when large quantities of dead organisms, usually zooplankton and algae, are buried underneath sedimentary rock and subjected intense heat and pressure.

what is the raw material used to make plastic

A plastic material is any of a wide rang of synthetic or semi-synthetic organic solids that are moldable plastics are typically organic polymers of high molecular mass, but they often contain other substances, The chemical composition of plastics is different depending on what type of plastic your dealing with But for the most part the raw material  of plastic is hydrocarbons found naturally in oil. 

greatest scientist of all time

SIR ISAAC NEWTON 

Sir Isaac Newton Born  25 December 1642 – 20 March 1726 was an English physicist and mathematician  who is widely recognised as one of the most influential scientists of all time and as a key figure in the scientific revolution. His book Philosophiæ Naturalis Principia Mathematica,  first published in 1687, laid the foundations for classical mechanics. Newton also made seminal contributions to optics and shares credit with Gottfried Leibniz for the invention of calculus.

Newton's Principia formulated the laws of motion and universal gravitation, which dominated scientists' view of the physical universe for the next three centuries. By deriving Kepler's laws of planetary motion from his mathematical description of gravity, and then using the same principles to account for the trajectories of comets, the tides, the precession of the equinoxes, and other phenomena, Newton removed the last doubts about the validity of the heliocentric model of the cosmos. This work also demonstrated that the motion of objects on Earth and of celestial bodies could be described by the same principles. His prediction that the Earth should be shaped as an oblate spheroid was later vindicated by the measurements of Maupertuis, La Condamine, and others, which helped convince most Continental European scientists of the superiority of Newtonian mechanics over the earlier system of Descartes.