A. Actually, a Tokra IS a Goauld.
B. A Goauld is a symbiote, whereas a Tokra is not.
C. Goaulds inhabit the bodies of humans, whereas Tokras do not.
D. A Goauld is a creature who inhabits a human. A Tokra is a human who serves as a vessel for a Goauld until it reaches maturity.