A controlled experiment is when the experimenter can change one variable in the experiment and completely change the results.
Redi experiment involved a closed jar with rotting meat on the inside. He waited for a few days and found no new forms of life in the jar.
He then did the same experiment, but this time he took the lid off the jar. After those few days he found there were maggots in the rotting meat from flies.
This is a great example of a controlled experiment, because he only had to change one variable to completely change the results. In this case that variable was just removing the lid from the jar.
Redi was trying to prove spontaneous generation with his experiment. Although, it failed.
Spontaneous generation: When life forms from non-livings.
Redi disproved spontaneous generation, but proved biogenesis.
Biogenesis: When life comes from other living beings.
He proved biogenesis because the flies had reproduced when the jar was opened.
Precipitation differences are the factor that does not contribute to "water stress" on the Earth.
<u>Explanation:</u>
- Less ocean water sources, population differences, Scarcity of economic water resources are the factor which leads to water stress on the Earth.
- Precipitation differences do not cause much difference in water stress. So it will not contribute to the water stress.
- An increase in population will cause major water stress because availability drinking water is less in the earth. Population increase can cause a major problem.
In Puerto Rico the earthquakes happen cause of that