Final answer:
Vascular plants, indicated by number 2 on the phylogenetic tree, possess vascular tissue consisting of xylem and phloem. This specialized tissue is responsible for the transport of fluids such as water and nutrients throughout the plant.
Step-by-step explanation:
The presence of vascular tissue unites the group of vascular plants indicated by number 2 on the phylogenetic tree.
Vascular tissue is specialized tissue that carries fluids such as water, nutrients, and sugars throughout the plant. It consists of two types of tissues: xylem, which transports water and minerals from the roots to the rest of the plant, and phloem, which transports sugars created during photosynthesis to other parts of the plant.
In contrast, non-vascular plants (mosses, liverworts, and hornworts) do not have vascular tissue and therefore do not belong to the group of plants with vascular tissue.