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How can natural selection create two different species from one species?

For speciation to occur, two populations of a species must become reproductively isolated. This can result from either the formation of a geographic barrier between two populations of the species, preventing...
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Answered by Sean K. • Biology tutor
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Guard cells open and close stoma in different conditions. When light intensity is high, potassium ions move into guard cells. Describe how this movement of potassium ions causes the stoma to open.

When the potassium ions move into the guard cells they increase the concentration. This causes water to move into the guard cells from more dilute areas by osmosis. The additional water leads to the guard ce...
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Answered by Emily W. • Biology tutor
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The genetic code is described as degenerate, universal and overlapping. Explain these terms.

The genetic code is universal because all species use the same four bases A,T,C and G, and each base sequence codes for the same amino acid in all species. despite the 64 possible codons (sequence of three b...
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Answered by Emily W. • Biology tutor
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Explain the sliding filament theory of muscle contraction

Muscle contraction begins after an action potential reaches the required muscle and causes the calcium ion protein channels on the sarcoplasmic reticulum to open. This allows the calcium ions to diffuse down...
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Answered by Isabel L. • Biology tutor
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b)Plants can use the glucose they have made to supply them with energy. Give four other ways in which plants use the glucose they have made.

To make starch, oil, amino acids and cellulose.
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Answered by Emma S. • Biology tutor
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