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loop

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Definition

In mathematics, a loop is a path that starts and ends at the same point. It can be a simple loop, like the path of a river, or it can be a more complex loop, like the path of a comet around the sun.

Loops are also used in computer science. A loop is a sequence of instructions that is repeated until a certain condition is met. For example, a loop can be used to print out a list of numbers or to calculate the factorial of a number.

Loops are a very powerful tool in computer science. They can be used to solve a wide variety of problems, and they are essential for many different programming languages.

How can the word be used?

The bird flew in a loop around the tree.

loop

Different forms of the word

Noun: A closed curve or line that returns to its starting point.

Verb: To form a loop or to move in a loop.

Adjective: Describing something that is shaped like a loop or that moves in a loop.

Etymology

The word "loop" comes from the Old English word "hlōp", which means "a coil" or "a ring". It was first used in English in the 10th century.

The Old English word "hlōp" is related to the Old Norse word "hlóp" and the German word "Häupel", which both mean "a coil" or "a ring".

The word "loop" is thought to be derived from a Proto-Germanic word that means "to coil". This is because a loop is a coiled or circular shape.

Question

What is a loop?

AQA Science Exam Question and Answer

Question:

Explain the concept of a feedback loop in the context of biological systems and provide an example to illustrate its functioning.

Answer:

  • A feedback loop is a fundamental concept in biology that describes a cyclic process where the output of a system affects its input, leading to a continuous loop of adjustments. This mechanism plays a crucial role in maintaining homeostasis and regulating various physiological processes in living organisms.
  • For instance, consider the regulation of body temperature. When the body's temperature deviates from its set point, sensors in the skin and brain detect the change and send this information to the brain's control centre. The brain processes this input and triggers a response, such as shivering or sweating, to bring the body temperature back to its optimal range. Once the body temperature returns to the set point, the feedback loop is closed, and the response ceases.
  • This example illustrates a negative feedback loop, where the body's response counteracts the initial change, aiming to restore equilibrium. Negative feedback loops are crucial for maintaining stability within an organism's internal environment.

In summary, a feedback loop is a dynamic process through which living systems regulate and maintain stability. This mechanism is essential for the proper functioning of biological processes, ensuring that conditions remain within an optimal range for the organism's survival and well-being.