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What are the key different types of selection?

Directional selection occurs when a phenotype at the extreme end of a distribution is favoured and so over time the distribution shifts in the direction of the favoured phenotype. An example of this is the d...
AC
Answered by Abigail C. • Biology tutor
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Why do you want to become a doctor instead of a different healthcare professional such as a nurse?

For this question you really need to understand the differences between the roles of a doctor compared to a nurse and to know your own motivations to study Medicine. Both positions provide help and care to p...
EK
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Calculate the relative formula mass of aluminium sulfate, Al2(SO4)3 (2 marks)

As the question is 2 marks, show working to ensure you get a mark even if answer is slightly wrongFrom periodic table you can see that the relative atomic masses are oxygen = 16; aluminium = 27; sulfur = 32(...
AS
Answered by Amy S. • Chemistry tutor
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Explain the reactivity of group 1 metals

The reactivity of group 1 metals increases as you go down the group. This is due the number of electron shells increasing, leading to the distance between the outermost electron and the nucleus. The increase...
JC
Answered by Jawad C. • Chemistry tutor
2638 Views

What is a Production Possibility Frontier?

A PPF is a graph that can be used to explain opportunity cost , and trade off. It is made up of a concave line with, for example, apples on the vertical axis and bananas on the horizontal axis. Since resourc...
MC
Answered by Maisie C. • Economics tutor
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