Melamine should be the right answer, i hope this helps.
I could only find 7!
- independent variable
- dependent variable
- control group
- experimental group
- constant
- observation
- inference
The answer is (3) metallic. Cobalt is a transition metal, so it can't be covalent bonds, which bond non-metals, therefore eliminating choice 1 and 2. Ionic bonds are between metals and non metals, but solid cobalt does not have a non metal, eliminating choice 4 as well. Metallic bonds are bonds between metals, therefore the answer is (3) metallic.
