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What are the adaptations of alveoli to increase gas exchange?

Alveoli are folded to increase their surface area to volume ratio, so more volume of air can diffuse in from the blood and and in from the bronchioles. The lining of the alveoli walls are also moist so the g...
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Answered by Lathesha B. • Biology tutor
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What is meant by the independent and dependent variables? Please give one example of each.

Independent variable: the one that you change. Dependent variable: the one that you measure. For example, a scientist wants to find out whether a diet including oats makes a horse run faster, so she adds oat...
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Answered by Lauren P. • Biology tutor
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How is an action potential formed when the neurone is stimulated?

When the neurone is stimulated , the Na+ channels open to allow influx of sodium ions down its electrochemical gradient. This makes the inside of the cell less negative. When threshold voltage (-55mV) is rea...
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Answered by Ismael C. • Biology tutor
3213 Views

Which component of the vaccine stimulates an immune defence? How do they prevent people from catching the disease e.g. mumps?

inactive pathogens white blood cells produce antibodies these antibodies can be then quickly released whrn the immune system comes into contact with the live pathogen and destoy it
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Answered by Ines R. • Biology tutor
3246 Views

Does water travel up or down the concentration gradient?

Via osmosis, water travels down the concentration gradient to an area of lower water concentration and higher concntration of other substances.
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Answered by Jenny R. • Biology tutor
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