There are different types of observers. Casual observers differ from scientific observer. Seeing and observing are two different things. Not that everybody seeing is actually observing the thing.
A casual observer just sits back and watch for something to happen while a scientific observer comes up with some hypothesis to work on it.
The problem you'll face if you don't have gliding joints in your body is : You won't be able to move shoulders.
Negative feedback serves a regulatory mechanism for reaction to avoid overproduction of a particular product.
<h3>What is negative feedback?</h3>
Negative feedback is a regulatory mechanism in which the products of a given reaction serves as inhibitor or regulator of a step in the reaction sequence so that more of the product is not produced.
Many enzymatic reactions in the body employ negative feedback for their regulation.
For example, high ATP concentration serves as negative feedback for glycolysis.
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Digestion starts in the "mouth" and continues in the stomach. The small intestine completes the digestion process.