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Draw a diagram showing a normal iris and what happens to the iris when a light in shined into the human eye. (1 mark). What causes this to happen? (2 marks)

(Any diagram showing an iris that has constricted) 1 mark In high light levels (1 mark) Accept reflex action due to increased photoreceptor action or words to that effect circular muscles relax and radial mu...
JP
Answered by James P. • Biology tutor
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For all values of x f(x) = x^2 + 2 g(x)= x - 5 show that fg(x) = x^2 -10x +27

Firstly, we have to substitute g(x) into the function f(x)So, fg(x) = (g(x))^2 +2 Next we must rewrite the equation on the RHS in terms of x only So, fg(x) = (x-5)^2 +2 Next we must simplify the RHS by expan...
YS
Answered by Yasmin S. • Maths tutor
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How is blood glucose levels controlled by the body (homeostasis) ?

Controlling high blood glucose Blood glucose levels are important to control because glucose is our key source of energy in respiration. When blood glucose levels are too high, this is detected by the pancre...
NB
Answered by Nazeya B. • Biology tutor
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In a village the number of houses and the number of flats are in the ratio 7 : 4 the number of flats and the number of bungalows are in the ratio 8 : 5 There are 50 bungalows in the village. How many houses are there in the village?

Good question! This is exactly the kind of question that could come up on the GCSE non-calculator paper. I think the main thing that makes this question tricky is sifting out the information and figuring out...
EJ
Answered by Ellie J. • Maths tutor
22293 Views

The point P has coordinates (3,4), Q has the coordinates (a,b), a line perpendicular to PQ is given by the equation 3x+2y=7. Find an expression for b in terms of a

Firstly, let's have a look through the question to find the key words and write down any equations you might need. Perpendicular means the two lines cross and meet at a right angle, we also have an equation ...
CB
Answered by Charles B. • Maths tutor
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