The second sentence we have the subordinating conjunction "even though" We never start a sentence with because so it's not the first one, despite having the conjunction.
Subordinating conjunctions to look for
"Until"
"Even though"
"If"
"When"
"because"
As the other person answered you do need a dependent and independent clause:
Example: Let me know if you need help.
Let me know is the independent clause. Another good hint is that the dependent clause usually starts with the conjunctions mentioned
The 1934 act built upon the Radio Act of 1927, which was a temporary measure when it was passed, intended to stabilize the burgeoning but chaotic radio industry of the mid-1920s. The 1934 act added communications via common carrier and television.
