What evidence exists that an electric current produces a magnetic field? What evidence exists that a changing magnetic field produces an electric current?

Develop two hypotheses to test the questions.

It won't lose or gain electrons if it's a covalent bond it shares the electrons with another atom or atoms. if it is an ionic bond it will lose the 3 electrons on the outer shell and become a positively charged ion.  credit goes to @sunshinebaby of answers.yahoo.com.

The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings. 

The answer is as follows in the photo