Common characteristics supporting the idea that the first land plants were related to green algae include .

Presence of chlorophyll  pigment in the leaves and cell walls were made of cellulose

Explanation:

The first plants that appeared on the land areas were comprised of the main component known as the cellulose that forms the cell wall of the plants and is responsible for making the various parts of plants such as branches, plant stems, and leaves, stronger and supportive.

In addition to this, the leaves of these primitive plants were comprised of green pigments known as chlorophyll that absorbs the sunlight and CO₂, and helps the plants in preparing the food for themselves as well as for the consumers, and also liberates oxygen (O₂) with it.

Thus, these are the two common characteristics that supported the idea that the primitive land plants had a relation with the green algae.

we would need to see the picture to answer it