The most common reaction that causes spoilage isn't a reaction at all. Molds and Bacteria are attracted to the easily found presence of water in the fruit. They find a natural place to reproduce and what they do causes spoilage.
Very few sources talk about the chemical changes that take place. If you put fruit in a refrigerator it slows the spoiling process down. That means that the chemical reaction has to be endothermic (it requires heat to occur)
The process of spoilage is speeded up by bananas for example, giving up Ethylene gas. You do not want to put a banana with tomatoes, because tomatoes are very sensitive to Ethylene. (It's OK to eat them together. They make a terrific salad. Yum).
I cannot find a definitive source that connects all this together, but the conduct of the fruit in refrigerators confirms what I am saying.
Spoilage is a very complex reaction and interaction with the environment. I have given you a hint of what happens but you should search it out to convince yourself of the outcome.
Answer:
B: They are the results of many experiments over a long period of time.
Explanation:
212 ml of lead nitrate is required to prepare a dilute solution of 820.7 ml of lead nitrate.
Answer:
Option A.
Explanation:
Similar to Avagadro's law, there is another law termed as dilution law. As the product of volume and normality of the reactant is equal to the product of volume and normality of the product from the Avagadro's law. In dilution law, it will be as product of volume and concentration of the solute of the reactant is equal to the product of volume and concentration of solution.

So, as per the given question C1 = 5.45 M of lead nitrate and V1 has to be found. While C2 is 1.41 M of lead nitrate and V2 is 820.7 ml.
Then, 

So nearly 212 ml of lead nitrate is required to prepare a dilute solution of 820.7 ml of lead nitrate.
Answer:option D is the correct answer, precipitation and it is because water is being released from the cloud into the earth.
Explanation:
PRECIPITATION is the process by which water condenses in the atmosphere. Precipitation can occur in form of snow,fog, dew,rain etc.
Atmospheric water is found in clouds and water vapor. Gradually and systematically the entire atmosphere rotates around the planet. When weather is being formed one of the most common results is precipitation.
In the water molecule activity here, precipitation will occur because water is being released from the atmosphere into the earth.
(D) exposure of a photographic plate