Which of these is an example of investigating an intensive property? weighing sand in a bag measuring the length of wire determining if a rock is magnetic recording the volume of water in a cylinder

Intensive properties are properties that are independent on the mass of a sample. Weighing sand in a bag exhibits an extensive property since the amount of sand in the bag matters. The length of the wire translates to the mass of the wire. The greater the length, the greater the mass of the wire. Volume as well is dependent on mass. Hence, the answer to this problem is the third option:determining if a rock is magnetic because whether the sample is taken small or at large, the property to be tested is still determined regardless of the size.

They carry out the exchange of gases as we breathe ( oxygen and carbon dioxide).