instruction:
In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
question:
Acrobats mount a single bicycle until _ people in all are stacked on top of it.
answer:
ten


question:
World population continues to rise, even as a few countries move toward _ growth.
answer:
zero


question:
Mood changes such as irritability, anger and depression usually settle within three or _ weeks.
answer:

four