instruction:
In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
question:
Normal adults appear to require _ to eight hours of sleep per day on average.
answer:
six

question:
B cells can receive stimulation in _ ways.
answer:
two

question:
Substance abuse knows _ boundaries crossing all cultural, ethnic, and socioeconomic lines.
answer:
no