Artificial quartz is produced
A
in Brazil
B
from tiny transistors
C
in an astonishing number of devices
D
with the help of thermionic valves
E
from natural crystals within steel cylinders
Verified Correct Answer: E.
Grammar & Contextual Explanation
The passage describes the process of making artificial quartz. It states that very small pieces of natural quartz crystal, which are imported from Brazil, are placed in long, narrow, steel cylinders. Inside these cylinders, high pressure and temperature are maintained for three weeks, causing the small fragments to grow into a larger quantity of quartz.
Source: Myschool Past Questions Archive (Record #14875)