Life on other planets should have cellular organization; ordered complexity; sensitivity; the ability to grow, develop, and reproduce; the ability to utilize energy; the ability to maintain homeostasis; and the ability to adapt via evolutionary change. Also, life on other worlds would be hierarchical in how it was organized.
Work Step by Step
These seven features are the main characteristics of life listed in the textbook and which can be induced from our observations of the natural world. If this were true for all life, anywhere, then these features should be found elsewhere in the universe where life is found. Other features, such as life depending on water, are probable but less certain than these features plus hierarchical organization.