The Biomass progression bar contains a total of twelve levels obtainable throughout the course of a game; it is visible at the top left corner for the Alien Commander at all times, and for Kharaa players when they access the Mini-map or the Evolve Menu.
Each constructed Hive provides one level of Biomass by default. The Alien Commander can research two additional Biomass levels from a single Hive using Team Resources; because Biomass level will increase by both methods, the Alien Commander can choose between base expansion by building a new Hive, or researching Biomass levels from the primary Hive. However, each Hive can only provide a maximum of three Biomass levels, so building new Hives is required to unlock the entire Kharaa tech-tree.
Each Biomass level will increase the maximum health pool of every Kharaa player, depending on different lifeforms. The health pool bonus will increase or decrease in accordance to the current Biomass level; if a Hive is destroyed, the passive Biomass level provided and any Biomass researched from that Hive will be lost, thus reducing maximum health for all Kharaa players in the process.
|Biomass Lifeform Max. Health Scaling|
|Lifeform||Health Per Level||Lv. 1 to 3||Lv. 4 to 6||Lv.7 to 9||Lv. 10 to 12|
|+3 max||70 / 73 / 76||79 / 82 / 85||88 / 91 / 97||100 / 103 / 106|
|+2 max||160 / 162 / 164||166 / 168 / 170||172 / 174 / 176||178 / 180 / 182|
|+2 max||125 / 127 / 129||131 / 133 / 135||137 / 139 / 141||143 / 145 / 147|
|+5 max||250 / 255 / 260||265 / 270 / 275||280 / 285 / 290||295 / 300 / 305|
|+25 max||900 / 925 / 950||975 / 1000 / 1025||1050 / 1075 / 1100||1125 / 1150 / 1175|
Biomass levels one to nine are requirements to unlock certain abilities for different Kharaa lifeforms. These abilities will become available after reaching the required Biomass levels and researching the associated lifeform upgrade from the Hive. Both requirements must be met to unlock abilities.
The five playable Kharaa lifeforms: Skulk, Gorge, Lerk, Fade, and Onos, have individual Lifeform Upgrades that, once researched, will automatically unlock abilities for all Kharaa players when the required Biomass levels are reached. The Biomass Levels table below shows the order of abilities from the Biomass progression bar.
|Biomass Levels & Unlocked Abilities|
|Level 1||Level 2||Level 3||Level 4||Level 5||Level 6||Level 7||Level 8||Level 9|
|Babbler Egg||Rupture||Bone Wall||Leap||Web||Spores||Stab||Stomp||Xenocide|
|Charge||Bile Bomb||Umbra||Bone Shield||Contamination|
|Gorge Egg||Fade Egg|
|Lerk Egg||Onos Egg|