Q: Does "On the other hand, instruments such as the acoustic guitar, once associated mainly with popular music, gained prominence in classical music in the 19th and 20th centuries." provide a valid answer to "What instrument gained prominence in the 19th and 20th century?"?
A: yes

Q: Does "The failure of negotiations over arms until 1955 was due mainly to the refusal of the Russians to permit any sort of inspections." provide a valid answer to "Why did nuclear arms negotiations with Russia fail prior to 1955?"?
A: yes

Q: Does "There are no vessels ("pores") in coniferous wood such as one sees so prominently in oak and ash, for example." provide a valid answer to "Besides oak, what's an example of a hardwood with prominent pores?"?
A: yes

Q: Does "Architectural "style" developed in the form of the Classical orders." provide a valid answer to "What ideals were Greek and Roman Classical architecture not based on?"?
A:
no