Related Clues:
- Absolutely necessary or life-giving
- Essential to life, indispensable
- Absolutely essential
- Of critical importance, decisive
- Essential to life or critically important
- Extremely important, essential to success
- Essential to life, most important
- Urgently needed or absolutely necessary
- Essential to life, critically important
- Most important, like certain body organs
- Vital, essential
- Crucially important
- 'Vital, essential (7)'
- Of extreme importance
- Of the greatest importance