Questions

Yes, a promise can be broken without being held.

When modifiers are misplaced or put in the wrong place, things can get quite confusing. A modifier adds detail or limits or changes the meaning of another word or phrase. 

Here Option A) "Covered in fluffiness, the couple played with the kitten" is the ony sentence contains a misplaced modifier. In the sentence, it gives the meaning that the couple are fluffy not the kitten.

In chemistry, Weak bonds are those forces of attraction that, do not take a large amount of energy to break.

For example, hydrogen bonds are broken by energies in the order of 4 - 5 kcal/mol.

Ionic bonds, hydrogen bonds and van der Waals interactions are considered weak bonds.

Weak bonds are transient and easily reversible.

Fuse Wire is Made of an alloy of Tin and Lead.

If too high a current flows, the element rises to a higher temperature and either directly melts, or else melts a soldered joint within the fuse, opening the circuit. Thefuse element is made of an alloy of Tin and Lead to provide stable and predictable characteristics.