Why are the number of systems found in plants smaller than the number of system found in animals?

The number of systems in plants is smaller than in animals primarily due to differences in complexity and functionality. Animals have multiple systems (e.g., circulatory, respiratory, nervous) that allow for mobility, interaction with the environment, and complex behaviors. In contrast, plants have fewer systems, as their primary functions—such as photosynthesis and nutrient absorption—are largely static and focused on growth and reproduction. This results in a more simplified system organization in plants compared to the intricate systems found in animals.