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What is the difference between active transport and diffusion.

Diffusion is the passive (does not require energy input) movement of a substance down a concentration gradient from an area of high concentration to an area of low concentration . Eg how the colour and flavo...
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Answered by Nicholas G. • Biology tutor
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How does speciation occur?

Speciation can be s ympatric (both populations in the s ame place ) or allopatric (populations in different places ). Speciation can result from natural selection and isolation. Natural Selection:1) A new se...
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Answered by Nicholas G. • Biology tutor
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How does the xylem structure of the plant help transpiration?

Firstly I would discuss with the student what transpiration is and what xylem vessels are. Transpiration is the inevitable consequence of gas exchange in the leaf causing water to be transported through the ...
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Answered by Robine V. • Biology tutor
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Explain the sequence of events that occur in the control of the cardiac cycle.

The sino-atrial node depolarises which causes a wave of excitation to pass through the atria (right prior to left) before reaching the atrio-ventricular node. The wave of excitation causes systole of the atr...
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Answered by Hannah G. • Biology tutor
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What is the difference between haploid and diploid cells? (2 Marks)

Diploid cells contain 2 sets of chromosomes (23 pairs of chromosomes) e.g. body cells . Haploid cells contain half the amount of chromosomes as diploid cells (only 1 set of chromosomes ) e.g. gametes.
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Answered by Katie D. • Biology tutor
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