TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: World population continues to rise, even as a few countries move toward _ growth.

SOLUTION: zero

PROBLEM: Young pandas mature very slowly and are almost _ months old before they are weened.

SOLUTION: six

PROBLEM: Primates are divided into _ subgroups.

SOLUTION:
two