For the first question, the answer would be D. (It supports the idea that living in a foreign country is the smartest way to learn a new language)
D: Language researchers found that students who lived in a foreign country learned the new language sixty-five percent faster than students learning at home.
The counterclaim is something that counteracts the statement. Therefore, for the second questions, the answer should be B.
B: However, learning to play an instrument has been proven to improve grades and test performance.
If you want my opinion, all these are a great thing to do.But
However answer B. Would be more reasonable to this question.
1. BENEFICIAL : producing a favorable result.
2. DERMATOLOGICAL : having to do branch of medicine concerned with the skin.
3. OSTEOARTHRITIC : having a degenerative bone disease.
4. PATHOLOGICAL : relating to or caused by disease.
5. CREDENTIAL : that which entitles one to confidence, credit, or authority.
6. POLYTHEISTIC : pertaining to the belief in more than one God.
They are
Clever
Generous
Sly