The two systems that work together to deliver oxygen are D, respiratory and cardiovascular
Explanation:
Typically, business software technologies are complex, and software strenuous. Business software applications are also often upgraded for changes in business goals or procedures. Real-time systems usually require a lot of hardware components that are quite difficult to change and cannot be upgraded Usually, actual-time safety critical systems that required to be built based on well-planned processes.
The answer is the first one
