Who finally disproved the theory of spontaneous generation

The Theory of Spontaneous Generation was finally disproved by the great French Chemist Louis Pasteur. The theory states that life forms are spontaneously created in organic matter. He disproved this theory by showing that the air is full of microorganisms. He did this by letting air pass through gun cotton filters that were dissolved with a mixture of ether and alcohol. He observed that the particles were released and settled at the bottom part of the liquid.  

Through this observation he revealed numerous microbes that resembled the types of bacteria found in petri dishes. This observation led him to disprove the theory because he concluded that bacteria present in the air would likely land on and contaminate any material exposed to it. 

The answer would be sand and gravel

Bis the correct answer.