Answer: (1.) Also, (4) however and (5) then are conjunction adverbs.
Explanation: Conjunctive adverbs are words used to connect two independent clauses or two separate sentences. Moreover, conjunctive adverbs can be used to show addition, comparison, contrast, result, and other types of relationships between clauses. "Also", "however" and "then" are three of the most common conjunctive adverbs. "Also" is used to indicate addition, while "however" is used to show contrast. "Then", on the other hand, is used to present a result or a consequence. "Unless" and "because" cannot be considered conjunctive adverbs since they are subordinating conjunctions.
