Biology 9700/51 May June 2018 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of photosynthesis rates in different leaf types by measuring the time for leaf discs to rise in sodium hydrogencarbonate solution, with a focus on standardized environmental conditions.

2. Calculation of photosynthetic rates from mean time for leaf disc buoyancy, and evaluation of conclusions about the influence of cuticle thickness, chlorophyll content, and C4 plant metabolism.

3. Use of colorimetry to quantify chlorophyll content in leaf extracts, involving calibration with a standard solution and measurements of light absorbance for comparative analysis.

4. Statistical analysis of chlorophyll concentration differences using a t-test, with justification of the number of tests and significance determination through degrees of freedom and critical value comparison.

5. Impact of woodland composition changes on red and grey squirrel habitats, with specific effects linked to tree species suitability and habitat alterations in England and Scotland.

6. Conservation strategies for red squirrels, including the effects of culling grey squirrels on SPPV spread, population dynamics on islands versus mainland, and implications of ecological competition.