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Explain how the use of antibiotics might lead to a resistant strain of bacteria arising.

-Antibiotics kill individual bacterial cells. Random mutation of the DNA in a bacterial cell might confer antibiotic resistance to that bacterial cell. A cell with the resistance mutation is less likely to b...
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Answered by Mark P. • Biology tutor
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Describe how water is carried by the transpiration stream. (3 marks)

Transpiration is the loss of water from a plant by evaporation, which then diffuses out of the leaf via the stomata. It is important to note whether the student understands how and why water leaves the plant...
AS
Answered by Abishek S. • Biology tutor
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What are the risks and benefits concerning genetic modification of crops?

With the world population increasing exponentially, the concept of genetic engineering can be viewed as a sustainable way to feed people. Crops can be genetically modified to improve certain characteristics ...
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Answered by Alyssa A. • Biology tutor
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Why are the lungs adapted for the rapid absorption of oxygen into the blood?

Oxygen is absorped into the blood by the process of diffusion. A large surface area, short diffusion pathway (the distance the oxygen has to travel through) and large concentration gradient increases the rat...
CP
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The drug Atropine blocks the action of of acetylcholine on structures innervated by post-ganglionic cholinergic neurones.

State precisely which part of the nervous system will be affected by atropine and suggest why atropine might be used during anesthesia. Answer: It acts on the parasympathetic branch of the autonomic nervous ...
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Answered by Rana M. • Biology tutor
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