Question

1. to det by pla derwa to the for th ment minu was eacl 30-s test eac

which statement represents a conclusion based on information in the g
1 there was a decrease in the a of phos - phorus dumped at site 2 from 1997.
2 pollution controls may have been to ef - fect at site 1 starting in 1995.
3 there was most likely no vegetation near site 2 from 1993 to 1994.
4 there was a greater variation in phospho concentration at site 1 than at site 2.

1. the concentration of salt in water affects the hatching of brine shrimp eggs. brine shrimp eggs will develop and hatch at room tempera - ture in glass containers of salt solution. describe a controlled experiment having three separate experimental groups that could be used to de - termine the best concentration of salt solution in which to hatch brine shrimp eggs. your answer must include:

1 • a description of how the control group and each of the three experimental groups will be different;
2 • two conditions that must be kept constant in the control group and the experimental groups;
3 • what data that should be collected, and how often; and
4 • one sample of experimental results that would indicate the best concentration of salt solution in which to hatch brine shrimp eggs.

Explanation:

1. Control - Experimental Group Difference: The control group would have a standard or no - salt solution, while the three experimental groups would have different concentrations of salt solutions (e.g., low, medium, high). This allows comparison to see which salt concentration is best for hatching.
2. Constant Conditions: Temperature (kept at room temperature) and the number of brine shrimp eggs in each container should be kept constant. This ensures that only the salt concentration variable affects the hatching process.
3. Data Collection: Count the number of hatched brine shrimp eggs in each group at regular intervals (e.g., every 12 hours). This data will show the hatching rate over time for each salt concentration.
4. Sample Experimental Result: If the group with the medium - concentration salt solution has the highest number of hatched eggs after a set period (e.g., 48 hours), it indicates that the medium - concentration salt solution is the best for hatching brine shrimp eggs.

Answer:

1. The control group has a standard or no - salt solution, and the experimental groups have low, medium, and high salt concentrations.
2. Temperature (room temperature) and number of eggs are kept constant.
3. Count the number of hatched eggs every 12 hours.
4. If the medium - concentration group has the most hatched eggs after 48 hours, it is the best concentration.