The labellings ‘a’ and ‘b’ for the Liverworts are:
a-Thallus and b-Roots
a-Gemma cups and b-Rhizoids
a-Thallus and b-Rhizoids
a-Gemma cups and b-Thallus
Both the plants are liverworts of Bryophytes, which have thalloid gametophytic body with rhizoids at the ventral side of the thallus.