Biology 9700/53 May June 2015 | Cambridge AS Level Past Papers With Mark Scheme

1. Testing the effectiveness of subtilisin A in contact lens cleaning solutions by measuring gelatin removal rate, including dilution preparation and control setup.

2. Identification of independent and dependent variables for the investigation of subtilisin A concentration effects on protein removal.

3. Graphical data representation to determine subtilisin A concentration in unknown cleaning solutions using interpolation.

4. Investigation of prenatal alcohol exposure effects on median nerve conduction speed in sensory and motor neurons at different postnatal stages.

5. Statistical analysis of conduction velocity differences using t-tests, formulation of null hypotheses, and reliability evaluation based on standard deviation.

6. Limitations in generalizing results from prenatal alcohol exposure studies due to sample size and controlled conditions.