Bas-

bass, basics, bassoon 

low

Cap, capt

captin, capital, caption

Cred

credit, credibility, credible

Dict 

dictionary, dictate, predict

Duc, duct 

ductape, duchess, inducted 

Fac, fact  

factor, fact, faction 

Graph 

graphic, biography, autograph

Log 

logged, login, biology

Mort 

mortal, immortal, mortified 

Scrib, script 

subscribe, subscription, description

Spec, spect 

spectate, special, spectacular 

Tact 

tactic, tactical, contact

Ten 

tentacles, tenacious, retentive 

Therm 

thermometer, thermostat, themosphere 

Ver 

verse, verification, very