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Megapode birds open and close the air vents of the nest at different times of the day. Suggest reasons why it is necessary to open and close the air vents.

There are a number of reasons why it is necessary to open and close the air vents. These include; allowing oxygen in, which is also necessary for respiration and allowing heat to escape. Closing the air vent...
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Answered by Davina R. Biology tutor
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y is proportional to x^2. When y is 75, x is 5. Find a formula for y in terms of x

y is proportional to x 2 so this means y = A*x 2 for some constant A. When y = 75, x = 5. Put these values in the formula above to find A: 75 = A*25 75/25 = A A = 3 So y = 3x 2
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Answered by Thomas M. Maths tutor
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Differentiate 4x^2 + 2ln3x + e^x

To differentiate x 2 you bring the power of x down, then reduce the power of x by 1, so d/dx(x 2 ) = 2x 1 ln3x differentiates to (d/dx(3x))/3x = 3/3x = 1/x e^x differentiates to (d/dx(x)) e^x = 1 e^x Therefo...
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Answered by Thomas M. Maths tutor
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Describe the photoelectric effect.

If we give a peice of gold negative charge and shine long wave, low frequency, electro-magnetic (E-M) radiation on it (for example radio waves) absolutely nothing will happen. If you start to shorten the wav...
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Answered by Umar S. Physics tutor
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What is diffusion?

For the exams, the definition you will need to know is that "diffusion is the net movement of a substance from an area of high concentration to an area of low concentration, down a diffusion gradient&qu...
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Answered by Emily R. Biology tutor
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