Answer:
Cats also purr when they are nervous or in pain, leading some experts to believe that this uniquely feline vocalization is actually a method of self-healing. A domestic cat's purr has a frequency of between 25 and 150 Hertz, which happens to be the frequency at which muscles and bones best grow and repair themselves.
Explanation:
Primary meristematic tissue helps the plant increase in length or vertical growth, meaning it helps the plant grow up toward the sun and down into the soil. It also helps a plant grow in thickness so that the roots and branches are stronger.
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The answer is <span>Take consistent amounts of saliva samples from a number of people who have not eaten in 8 hours and measure the quantity of amylase in each sample.
First, the researcher needs to know the quantity of amylase in the <u>same</u> amount of saliva. Thus the amount must be consistent and not varying.
Next, people must not eat in 8 hours, so they are all in the same condition at the moment of collecting saliva. If some eat immediately before the sample collecting while some eat 8 hours before, the content of their saliva will be different.
For the correct results, all conditions must be the same.</span>
