Pasteur produced a nutrient broth and placed equal amounts of it in two long necked flasks. One flask had a straight neck (control) and the other had a swan shaped bent neck (being tested). He boiled the broth in both the flasks to kill any living organism that might be surviving on it. The two flasks were then left in the open air of the room to cool down. After several days passed, Pasteur noticed that the broth in the straight necked flask had changed its color but the swan necked flask didn't. From this observation he was able to conclude that the straight necked flask had let the organisms enter the flask and contaminate the broth. The swan necked flask blocked the entry of the organisms from the open air and thus remained unaffected.
<span>300BC was the approximate year.
</span>
Answer:
2, that’s what the 2 means.
Explanation:
Carbon cycle is process that shows the exchnge of carbon in the living and atmospheric system. Carbon cycle starts with the giving off of carbon dioxide from nimals, accumulation of co2 of plants, contribution of organic matter of dead animals and plants, photosynthesis, etc. The answer is D. fermentation