life·blood 
(līfblŭd′)
(līfblŭd′)n.
1. Blood regarded as essential for life.
2. An indispensable or vital part: Capable workers are the lifeblood of the business.
- beta carotene
- beta-carotene
- beta cell
- beta decay
- beta-endorphin
- beta error
- beta globulin
- betaine
- beta interferon
- Beta Israel
- betake
- beta-lactam
- beta-lactam antibiotic
- beta-lactamase
- betamethasone
- beta-oxidation
- beta particle
- beta ray
- beta-receptor
- beta rhythm
- beta sheet
- beta test
- beta-test
- betatron
- beta wave