Answer: The second sentence.
Explanation: The second sentence uses the conjunctive adverb likewise to introduce a similar idea to the one in the first clause. Conjunctive adverbs are words that connect two independent clauses and signal a relationship between them.
The first sentence does not use a conjunctive adverb, as the two clauses are simply connected by a comma.
Here are some other examples of conjunctive adverbs:
however
therefore
moreover
consequently
nevertheless
besides
nonetheless
furthermore
in addition
as a result
for this reason
on the other hand
on the contrary
I hope this answer helps.