9.9 A celery stalk was placed into a beaker of blue dye. W…

9.9 A celery stalk was placed into a beaker of blue dye. When the dye reached the leaves, the stalk was taken out and a section was cut, as shown in the diagram     Right-click on the blue button to open Fig 9.9(a)         Which diagram shows the appearance of the cut end of the stalk? (1)   Right-click on the blue button to open Fig 9.9(b) to see your options.      

1 The cardiac cycle describes the sequence of events takin…

1 The cardiac cycle describes the sequence of events taking place in the heart to bring about changes in blood pressure.     The graph below shows the changes in blood pressure in the aorta, left ventricle, and left atrium.     Right-click on the blue button to open Figure 1.1        

5.2 The diagram shows the structure of thymine and four ot…

5.2 The diagram shows the structure of thymine and four other bases, P, Q, R and S. Bases P and S can form three hydrogen bonds each and bases Q and R can form two hydrogen bonds each.     Explain which of the four bases P, Q, R or S is adenine. (2)   Right-click on the blue button to open Fig 5.2