Here's why:

* Diversity of Life: The diversity of multicellular organisms is vast. From simple organisms like sponges to complex ones like humans, there's a huge range in body plans and structures.

* Organ Systems: Different organisms have different organ systems, designed to suit their specific environments and lifestyles. For example, plants have vascular systems for transporting water and nutrients, while animals have digestive systems for breaking down food.

* Organ Types: Even within the same organ system, the types of organs can vary. For instance, mammals have a four-chambered heart, while reptiles have a three-chambered heart.

* Organ Number: The number of organs within a system can also vary. For example, humans have two lungs, while some reptiles have only one lung.

In conclusion: It's important to understand that multicellular organisms have evolved different organ systems and organ types based on their evolutionary history and adaptations. Therefore, claiming they all have the same type and number of organs is a gross oversimplification.