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Explain how allopatric speciation can lead to the formation of 2 species from an ancestral species?

The ancestral species is split into two populations by a geographic barrier, which prevents gene flow. Mutations arise which causes genetic variation between the populations. There are different environmenta...
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Answered by Seb H. • Biology tutor
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Prove that (2*a^2 + 7a + 3)/(a + 3) is an odd number for any positive integer number, a.

We see that the numerator is a quadratic, so we factorise it to obtain: (2 a + 1)(a + 3)/(a + 3) = 2 a + 1 Since a is a positive integer, we know that 2*a + 1 will always be an odd number.
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Answered by Nadia M. • Maths tutor
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Find the length of the hypotenuse if the right angled triangle's other two sides are of length 5cm and 12cm.

Use of a^2+b^2=c^2 must be included in the answer. Furthermore the numbers must be put in the above equation to give: 5^2+12^2=c^2 This must then be solved to give: 169^0.5=c The answer can be found without ...
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Answered by Sarah W. • Maths tutor
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4x^2 + 8x + 3 can be written in the form a(x + b)^2 + c where a, b and c are whole numbers. Work out the values of a, b and c.

Factorise 4x 2 + 8x + 3 = 4(x 2 + 2x + 3/4) divide the coefficient of x by 2: 2/2=1 Now x 2 +2x = (x+1) 2 -1 2 = (x+1) 2 -1 Hence, 4((x+1) 2 -1+3/4) = 4(x+1) 2 -1 which is of the form a(x + b) 2 + c So a=4, ...
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Answered by Donny W. • Maths tutor
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Outline the main differences between an artery and a vein? (6 marks)

An artery carries blood away from the heart. The blood is oxygenated with the exception of the pulmonary and umbilical artery. The vessel must cope with high pressure demands and therefore has thick, elastic...
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Answered by Katy B. • Biology tutor
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