Question

omar observes that many buildings in his city were built using limestone. he also knows that limestone reacts with acids and that chemical reactions are affected by temperature. with this in mind, he conducts an investigation to see how the amount of damage to the limestone is affected by the amount of acid on the stone. which statement describes the correct plan for his procedure? the temperature and the amount of damage to the limestone are variables. the amount of acid and the type of limestone are controls. the temperature and the amount of acid are variables. the type of limestone and the amount of damage to the limestone are controls. the amount of acid and the amount of damage to the limestone are variables. the temperature and the type of limestone are controls. the amount of acid and the type of limestone are variables. the temperature and the amount of damage to the limestone are controls.

Explanation:

In an experiment, variables are what is being tested and changed, while controls are kept constant. Here, the temperature and the amount of acid affect the damage to limestone, so they are variables. The type of limestone can be kept the same and is a control.

Answer:

The temperature and the amount of acid are variables. The type of limestone is a control.