Bryophytes are non vascular plants which include, mosses, liverworts and hornworts. They are seedless and lack specialized water conducting tissues.
Vacular plants are those plants that use specialized tissues to transport food and water to all parts of the plant. They have a root system, vascular system and also a shoot system. The dominant stage of the life cycle in vascular plants is the sporophyte.
Leukemia can be treated using human stem cells to attack and destroy cancer cells.
The answer is the second and third answers. Kingdom Protista is a polyphyletic taxon, meaning they did not evolve from one common ancestor, unlike what you see from a monophyletic taxon. Because they come from multiple ancestors, they share more similarities with other organisms from other kingdoms, rather than themselves.