Final answer:
Land plants are most likely descended from green algae, specifically the Charophytes group, due to shared characteristics like photosynthetic pigments, cellular structure, and reproductive strategies.
Step-by-step explanation:
The correct answer to the question of which group the land plants are probably descendants of is green algae. Specifically, the Charophytes, a subgroup of green algae, are considered to be the closest living relatives to land plants. This is due to several shared characteristics such as a similar mechanism of cell division, biochemical pathways, chlorophyll a and chlorophyll b as photosynthetic pigments, cellulose in cell walls, and the storage of carbohydrates as starch. The Archaeplastida supergroup includes green algae, red algae, and land plants. However, it is the green algae, particularly the Charophytes, that exhibit the closest resemblance to land plants in morphology and reproductive strategies.