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What are the key features of natural selection?

First off we need to understand what natural selection is. Natural selection is the mechanism proposed by Charles Darwin in his theory of evolution.
The key points you need to know for this are:

Answered by Amy W. • Biology tutor

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What is the difference between homozygous and heterozygous?

Homozygous means there are two copies of the same allele present at a specific locus (position) on a chromosome, e.g. two copies of the allele for blue eyes. Whereas, heterozygous means there are two copi...

Answered by Amy W. • Biology tutor

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What is an allele?

Simply put, it is a form of a gene which can lead to different phenotypes, e.g. eye colour. There is one allele that codes for blue eyes and another allele that codes for brown eyes.

Answered by Amy W. • Biology tutor

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What is a punnett square?

A punnett square is a diagram that is used to predict the outcome of a particular cross or breeding experiment. This can be used for plants, animals and humans.

Answered by Amy W. • Biology tutor

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I don't understand the difference between aerobic and anaerobic respiration

Aerobic respiration is respiration that uses oxygen and glucose, whilst anaerobic respiration is respiration that only uses glucose. As you can see in the equations for both types of respiration:

Answered by Arabella K. • Biology tutor

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