Living Environment Regents Practice Test

Which system in multicellular organisms is comparable to the function of cytoplasm in single-celled organisms?

1. Nervous system

2. Endocrine system

3. Circulatory system

4. Digestive system

The correct answer is: Circulatory system

The circulatory system in multicellular organisms is comparable to the function of the cytoplasm in single-celled organisms because it plays a crucial role in transporting essential substances throughout the body. In single-celled organisms, the cytoplasm serves as the medium that holds organelles and facilitates the movement of nutrients, waste, and other molecules within the cell. Similarly, the circulatory system is responsible for distributing nutrients, oxygen, hormones, and removing waste products from cells in multicellular organisms. It ensures that all cells receive what they need to function properly, much like the cytoplasm supports cellular processes in single-celled organisms. The other systems mentioned in the options serve different functions. The nervous system primarily transmits signals for communication and coordination, the endocrine system regulates hormonal functions and metabolic processes, and the digestive system is responsible for breaking down food and absorbing nutrients. Each of these systems has specific roles that do not directly correspond to the transport and supportive functions provided by cytoplasm in single-celled organisms.