heat the mixture filter the mixture pour water into the mixture pull a magnet through the mixture
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A container is filled with a mixture of sand and an unknown substance. What should a student do to determine whether iron particles are in the mixture?
Possibilities:
- heat the mixture
- filter the mixture
- pour water into the mixture
- pull a magnet through the mixture

pull a magnet through the mixture