1. A researcher is studying the effects of a new drug on the growth of cancer cells in a petri dish. They expose the cancer cells to different concentrations of the drug and measure the percentage of cells that survive after 48 hours. The researcher wants to determine the half-maximal effective concentration (EC50) of the drug, which is the concentration at which 50% of the cells are killed. Which of the following methods would be most appropriate for the researcher to use to calculate the EC50?

2. A researcher is studying the effects of a new drug on the survival of cancer cells in a petri dish. They expose the cancer cells to different concentrations of the drug and measure the percentage of cells that survive after 48 hours. The researcher wants to determine the minimum concentration of the drug that is effective in killing at least 80% of the cancer cells. Which of the following methods would be most appropriate for the researcher to use to determine this?

3. A scientist is studying the effects of a new drug on the growth of bacteria. They inoculate 4 petri dishes with the same strain of bacteria and expose them to different concentrations of the drug. After 24 hours, they measure the diameter of the bacterial colonies in each dish. Which of the following is the best way for the scientist to analyze the data and determine the effect of the drug concentration on bacterial growth?

4. A researcher is investigating the effect of light intensity on the rate of photosynthesis in a plant. They set up four experiments, each with the same plant species and growth conditions, but with different light intensities: 100 lux, 500 lux, 1000 lux, and 2000 lux. They measure the rate of oxygen production in each experiment as an indicator of the rate of photosynthesis. Which of the following graphs would best represent the relationship between light intensity and the rate of photosynthesis?

5. A researcher is investigating the effect of pH on the activity of an enzyme. They set up five experiments, each with the same concentration of enzyme and substrate, but at different pH levels: 4.0, 5.0, 6.0, 7.0, and 8.0. They measure the rate of product formation in each experiment. The results show that the enzyme activity is highest at pH 7.0 and decreases as the pH deviates from this value. Which of the following factors could explain the observed relationship between pH and enzyme activity?

6. A biologist is studying the effect of different nutrient concentrations on the growth of a plant species. They plant the same number of seedlings in four different nutrient solutions and measure the height of the plants after a fixed time. Which of the following is the best way to analyze the data and determine the effect of nutrient concentration on plant growth?

7. A researcher wants to investigate the relationship between the amount of sunlight a plant receives and its growth rate. They set up an experiment with 4 groups of plants, each receiving a different amount of sunlight per day (2 hours, 4 hours, 6 hours, and 8 hours). After 4 weeks, they measure the height of each plant. Which statistical test should the researcher use to analyze the data and determine if there is a significant difference in growth rate between the groups?

8. A researcher is investigating the relationship between the amount of rainfall and the yield of a crop. They collect data on the annual rainfall and crop yield for a region over a 20-year period. Which statistical analysis should the researcher use to determine the strength and direction of the relationship between rainfall and crop yield?

9. A researcher is investigating the effect of light intensity on the rate of photosynthesis in a plant. They set up four experiments, each with the same plant species and growth conditions, but with different light intensities: 100 lux, 500 lux, 1000 lux, and 2000 lux. They measure the rate of oxygen production in each experiment as an indicator of the rate of photosynthesis. The results show that as the light intensity increases, the rate of photosynthesis increases, but only up to a certain point. Beyond this point, the rate of photosynthesis decreases. Which of the following conclusions can be drawn from these results?

10. A biologist is studying the relationship between the size of a bird species and its habitat. They collect data on the body size and the type of habitat (e.g., forest, grassland, urban) for a sample of birds. Which statistical analysis should the biologist use to determine if there is a significant difference in body size between birds from different habitats?