Final answer:
All life on Earth is interconnected through evolution. Biologists construct phylogenetic trees to show the relationships among different organisms and illustrate their evolutionary history.
Step-by-step explanation:
All life on Earth is interconnected through evolution. Evolutionary theory states that all organisms, including humans, plants, and bacteria, share a common ancestor. Biologists construct phylogenetic trees to illustrate how different organisms are related and to show the relationships among them. These trees demonstrate the evolutionary history of life forms and how they have diverged and adapted over time.