12 times breathe give 240 ml of pure 
. Each breathe gives 20 ml of .
Let us consider, volume of air per breathe= x ml.
Pure from inhaled air= 
ml and Pure from exhaled air= 
ml.
Pure from inhaled and exhaled air= 20 ml
So, + = 20
Therefore, x = 55.5 ml
So, volume of air per breath= 55.5 ml.
Chemical properties is when a material undergoes a chemical change or reaction like a nail rusting and a physical change can be observed without changing the material like temperature, color, texture, odor,etc.
Answer: The correct option is heterogeneous mixture whose components are attracted differently to a magnet.
Explanation: There are two types of mixtures:
1) Homogeneous mixtures: In these mixtures, the particles are uniformly distributed throughout the mixture. These particles cannot be separated.
2) Heterogeneous Mixtures: These are the mixtures where the particles are visible separated and are not-uniformly distributed. These particles can be separated easily.
If magnet is used to separate the components of a mixture, the heterogeneous mixtures will only get separated.
To separate the components by a magnet, the components of a mixture should attract the magnet differently. One component should attract the magnet and another should not. Hence, they can be easily separated.
Answer:
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