The correct answer would be the second option. The correct plan for his experiment would be that the temperature, the type of limestone, and the type of acid are controls. The amount of acid and the amount of damage to the limestone are variables. To determine the degree of damage of the acid it would be best that the amount of acid is the manipulated variable while everything else are assumed constant.
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Answer: Battle of the somme
Explanation:
Answer: Rising prices give a signal to consumers to reduce demand or withdraw from a market completely, and they give a signal to potential producers to enter a market. Conversely, falling prices give a positive message to consumers to enter a market while sending a negative signal to producers to leave a market.
Explanation: Hopefully this helps you with whatever you are doing. This is a long answer. Hopefully you will get extra credit for this answer