C.
Ionic bonds are formed between metal atoms, potassium in this case, and non-metal atoms, iodine in this case.
In order to increase the strength of his electromagnet and pick up more thumbtacks Braddy should use two batteries instead of one. Using two batteries will increase the amount of current in the coils which will induce a higher electromagnetic field in the nail.
Another option would be to increase the number of coils of wire.
Answer:
Nitrogen and Carbon
Explanation:
Nitogen cycle and carbon cycle are the two biogeochemical cycles
