Q: Does "for the time being there is no indication which method is at fault." provide a valid answer to "Why does this difficulty occur?"?
A: no

Q: Does "The dynamic or moving coil microphone was introduced around 1930 and the velocity or ribbon microphone in 1932." provide a valid answer to "What are two examples of high quality microphones?"?
A: yes

Q: Does "However, this was repealed in 81 BC and a property tax rate of two coins for every 0.2 L (0.05 gallons) was levied for those who traded it privately." provide a valid answer to "In what year did the liquor industry once again become privatized?"?
A: yes

Q: Does "Mathematical objects are often examined by associating groups to them and studying the properties of the corresponding groups." provide a valid answer to "What are usually analyzed by associating groups to them and studying the elements of the corresponding groups?"?
A:
yes