Rearrange the given phrases to form a sentence with superlative degree of comparison:

of all the metals | Iron | is the | most useful.

Iron is the most useful of all the metals.

The correct answer is option 2. Iron is the most useful of all the metals.

The sentence "Iron is the most useful of all the metals." compares iron to all other metals and establishes that iron is the most useful among them, indicating the superlative degree of comparison.

Breaking down the sentence:

"Iron": This is the subject of the sentence, referring to the metal.

"is": This is the linking verb that connects the subject "iron" to the complement "the most useful of all the metals."

"the most useful": This is the superlative form of the adjective "useful," indicating that iron has the highest degree of usefulness among all metals.

"of all the metals": This phrase specifies the scope of the comparison, indicating that iron is compared to all other metals.

Together, the sentence asserts that iron holds the highest level of utility when compared to all other metals. It highlights iron's significance and usefulness in comparison to its metallic counterparts.