The correct option is (c) 1 and 3 only
Explanation
Simple aquatic animals like Sponges (Phylum Porifera) and Hydra (Phylum Cnidaria) do not possess complex organ systems. Instead of a specialized circulatory system, they utilize the surrounding water to transport substances essential for survival.
Statement 1 is Correct:
Sponges and Hydra are lower invertebrates that lack a circulatory system with blood and blood vessels. They do not have a fluid like blood to transport nutrients and oxygen throughout the body.
Statement 2 is Incorrect:
The water entering their bodies brings food and oxygen. The phrasing "carries away" implies the removal of these substances, which is factually incorrect. The inflow of water serves as the mechanism for the intake of essential nutrients and dissolved oxygen.
Statement 3 is Correct:
As the water moves out of their bodies, it carries away waste materials and carbon dioxide. This continuous flow of water ensures the removal of metabolic by-products, effectively functioning as an excretory mechanism.
Key Takeaway:
In simple organisms like Sponges and Hydra, environmental water circulates through body cavities, acting as a substitute for blood by bringing in nutrients and oxygen while removing waste products.