Modifiers matching oxygen:

• bound,
• molecular,
• dissolved,
• active,
• elemental,
• free,
• atomic,
• pure,
• abundant,

Simple categories matching active:

• ectotherm,
• sensation,
• agonist,
• substance,
• metal,
• compound,
• material,
• experience,
• sport,
• infection,
• rest,
• tumor,
• carnivore,
• function,
• packing,
• amusement,
• tissue,
• predator,
• activity,
• organism,
• factor,
• coolant,
• fraction,
• fertilizer,
• component,
• star,
• growth,
• emotion,
• measure,
• subject,
• estrogen,
• molecule,
• scavenger,
• owner,
• science,
• means,
• connection,
• individual,
• mechanism,
• action,
• plant,
• constituent,
• phytochemical,
• card,
• metabolite,
• analgesic,
• athlete,
• macromolecule,
• alloy,
• user,
• radical,
• institution,
• trap,
• filter,
• income,
• isomer,
• fun,
• participation,
• fauna,
• monomer,
• lipid,
• defence,
• vehicle,
• ketone,
• alkaloid,
• halogen,
• country,
• database,
• arthritis,
• restoration,
• protocol,
• food,
• hardware,
• enzyme,
• operation,
• peptide,
• situation,
• acid,
• sedative,
• industry,
• nekton,
• progestin,
• alarm,
• command,
• recreation,
• chlorine,
• subsystem,
• quality,
• play,
• neurohormone,
• thing,
• relay,
• repeater,
• use,
• teleost,
• competition,
• pigment,
• code,
• intervention,
• system,
• anticoagulant,
• elimination,
• endeavour,
• corticosteroid,
• precursor,
• gadget,
• carbon,
• therapy,
• region,
• outing,
• soil,
• lysozyme,
• structure,
• party,
• waterway,
• layer,
• decay,
• contamination,
• sentiment,
• shoes,
• attraction,
• domain,
• prey,
• area,
• detector,
• society,
• market,
• works,
• control,
• graphics,
• disorder,
• chemical,
• block,
• profession,
• benzodiazepine,
• occupation,
• snake,
• species,
• room,
• solute,
• date,
• switch,
• file,
• indication,
• ligand,
• element,
• property,
• oxygen,
• exercise,
• mammal,
• event,
• contaminant,
• employment,
• phagocyte,
• feature,
• form,
• union,
• defense,
• development,
• response,
• process,
• hydrogen,
• atom,
• neuroleptic,
• firewall,
• arts,
• catalyst,
• bacteria,
• virus,
• education,
• falcon,
• motion,
• galaxy,
• gas,
• ester,
• ingredient,
• pet,
• antimetabolite,
• carrier,
• clay,
• anesthetic,
• device,
• mineral,
• nucleotide,
• instrumentation,
• safety,
• amine,
• male,
• foundation,
• elements,
• unit,
• filler,
• iud,
• medium,
• female,
• repository,
• street,
• option,
• engagement,
• document,
• array,
• lesion,
• radiator,
• stimulation,
• polypeptide,
• equipment,
• moiety,
• impurity,
• formation,
• corticoid,
• yeast,
• proteinase,
• module,
• solvent,
• cytokine,
• radar,
• particle,
• environment,
• oxide,
• condition,
• tuberculosis,
• matter,
• glucocorticoid,
• residue,
• invertebrate,
• antigen,
• insect,
• adulterant,
• buffer,
• stimulant,
• carotenoid,
• widget,
• sensor,
• crime,
• atmosphere,
• micronutrient,
• medication,
• behavior,
• product,
• limb,
• steroid,
• waste,
• dog,
• procedure,
• operations,
• preparation,
• disease,
• organs,
• pesticide,
• androgen,
• symptom,
• cancer,
• game,
• mixer,
• source,
• polysaccharide,
• protease,
• allergen,
• interface,
• usage,
• drug,
• creature,
• object,
• people,
• line,
• state,
• business,
• holiday,
• membrane,
• polymer,
• br,
• antibiotic,
• intermediate,
• service,
• organization,
• portion,
• muscle,
• pathology,
• practice,
• receptor,
• person,
• protein,
• treatment,
• directory,
• volatile,
• hormone,
• group,
• basin,
• issue,
• order,
• microorganism,
• task,
• hydrocolloid,
• support,
• body,
• modality,
• display,
• salt,
• alcohol,
• alkali,
• force,
• ministry,
• depressant,
• ability,
• movement,
• devices,
• passion,
• space,
• interaction,
• worm,
• effort,
• touch,
• entertainment,
• fabric,
• backpacker,
• problem,
• phosphatase,
• illness,
• livestock,
• aldehyde,
• work,
• antidepressant,
• part,
• organ,
• behaviour,
• discipline,
• relative,
• information,
• cell,
• pursuit,
• substrate,
• instrument,
• medicine,
• herb,
• ir,
• item,
• animal,
• toy,
• place,
• surface,
• change,
• carbonate,
• rift,
• agent,
• phenomenon,
• class,
• entity,
• anode,
• solid,
• endeavor,
• load,
• content,
• facility,
• zone,
• fish,
• cation,
• song,
• job,