excretory and skeletal systems nervous and endocrine systems circulatory and digestive systems respiratory and circulatory systems
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which two systems primarily function to rid the human body of the wastes resulting from cellular energy production?
Possibilities:
- excretory and skeletal systems
- nervous and endocrine systems
- circulatory and digestive systems
- respiratory and circulatory systems

respiratory and circulatory systems