Statement A : Louis Pasteur demonstrated that life comes only from pre-existing life.
Statement B : S.L. Miller observed that electric discharge in a flask containing  $C{H}_4,H_2,N{H}_3$  and water vapours at 800ºC forms amino acids.

Louis Pasteur's experiments played a crucial role in refuting the idea of spontaneous generation and providing experimental evidence for the principle of biogenesis, which states that life arises only from pre-existing life. Spontaneous generation was a prevailing belief that suggested living organisms could arise spontaneously from non-living matter. Pasteur's work was instrumental in dispelling this notion and establishing a foundation for the modern understanding of the origin of life.

Stanley L. Miller, in 1953, conducted a groundbreaking experiment known as the Miller-Urey experiment, which aimed to simulate the conditions believed to have existed on early Earth. The goal was to investigate the possibility of the spontaneous formation of organic molecules, particularly amino acids—the building blocks of proteins—from simple inorganic precursors.

The experiment was designed to mimic the primordial Earth's atmosphere, which was thought to be composed of methane (CH₄), ammonia (NH₃), hydrogen (H₂), and water vapor (H₂O). Miller set up a closed system containing these gases, representing the early atmosphere, and subjected it to electric discharge to simulate lightning, which was hypothesized to be a common occurrence in the early Earth.

The conditions in the system included a flask with the simulated atmosphere, which was then subjected to electrical sparks to simulate the energy provided by lightning. After running the experiment for a week, Miller observed that the gaseous mixture had undergone chemical reactions, and when the resulting compounds were analyzed, he found the presence of amino acids. Amino acids are the building blocks of proteins and are essential for life as we know it.