23. Economic systems
natural systems.
a. operate within
b. are independent of
c. have no relation to
d. are equal to

showing a photograph would make this a hell of alot easier

the answer is d p: cell, q: organ, r: organ system, s: tissue

those characteristics are cellular organization, reproduction, metabolism, homeostasis, heredity, response to stimuli, growth and development, and adaptation through evolution. some things, such as a virus, demonstrate only a few of these characteristics and are, therefore, not alive