Related Clues:

• Underlying reason
• Revolutionist's need
• Baby part
• Shout of approval
• Firmly establish
• ''Bravo!'' or ''Hurrah!''
• Rooted for
• Darwin's "The __ of Species"
• River's beginning
• Lowest part
• Underground plant part
• Beginning point
• Potato or yam, e.g.
• Taro or potato
• Shakespearean weaver