Almost everything imaginable pollutes the water, whether it be plastic cans or dumping beverages into the ocean
Answer:
Option (D)
Explanation:
In terms of chemistry, a catalyst is usually defined as the substance that is commonly used in a reaction in order to increase the rate of reaction, without getting consumed. It helps in the reduction of activation energy.
In the given case, the lever or a person can be considered as a catalyst because both of these will increase the efficiency (or rate) in removing the rock from the top of the perch. Thus, the lever or the human will remain the same after the removal of rock as a catalyst can be recovered after the reaction.
Therefore, the correct answer is option (D).
No, the solution with bacteria in it needs to be diluted in order to be in the range of 30 – 300.
A colony-forming unit –CFU is used to estimate the number of viable (ability to divide by binary fission) microbes in a sample.
A sample of microbes is diluted and spread on a plate. Then, the number of colonies is counted, assuming that each colony have grown from a single colony-forming unit, or CFU.
Plates with more than 300 colonies are difficult to count while those with less than 30 colonies give statistically unreliable numbers of colonies to count.
Lichens have been described as "dual organisms<span>" because they are symbiotic associations between two (or sometimes more) entirely different types of microorganism - a fungus (termed the mycobiont) a green alga or a cyanobacterium (termed the photobiont).
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