Question

1. the concentration of salt in water affects the hatching of brine shrimp eggs. brine shrimp eggs will develop and hatch at room temperature in glass containers of salt solution. describe a controlled experiment having three separate experimental groups that could be used to determine the best concentration of salt solution in which to hatch brine shrimp eggs. your answer must include: - a description of how the control group and each of the three experimental groups will be different; - two conditions that must be kept constant in the control group and the experimental groups; - what data that should be collected, and how often; and - one sample of experimental results that would indicate the best concentration of salt solution in which to hatch brine shrimp eggs. 29. a student hypothesized that lettuce seeds would not sprout (germinate) unless they were placed in the dark. the student planted 10 lettuce seeds in soil that was kept in the dark and planted another 10 lettuce seeds in soil that was exposed to light. the data collected are shown in the following table.

Explanation:

Step1: Define control and experimental groups

The control group could have a standard - known concentration of salt solution (e.g., a concentration that is commonly used or a baseline value). The three experimental groups would have different concentrations of salt solution, one with a lower concentration than the control, one with a higher concentration, and one with a concentration in - between.

Step2: Identify constant conditions

1. Temperature: Keep all containers at room temperature to ensure that temperature does not affect the hatching process.
2. Egg quantity and quality: Use the same number of brine - shrimp eggs of similar quality in each container.

Step3: Determine data collection

Count the number of hatched brine - shrimp eggs in each container every hour for 24 hours. This will show the rate and total number of hatched eggs over time.

Step4: Analyze experimental results

If one of the experimental groups has a significantly higher number of hatched eggs compared to the control group and the other experimental groups after 24 hours, then the salt - solution concentration of that group is likely the best for hatching brine - shrimp eggs.

Answer:

Control group has a standard salt - solution concentration. Experimental groups have different concentrations (lower, higher, and in - between). Constant conditions are temperature (room temperature) and egg quantity/quality. Collect data by counting hatched eggs every hour for 24 hours. If an experimental group has the most hatched eggs after 24 hours, its salt - solution concentration is the best.