Which among the following is trueAll vertebrates have open circulatory systemAll chordates have closed circulatory system All chordates are vertebratesAll vertebrates are chordates

To determine which statement is true among the given options, let's analyze each statement step by step:

1. "All vertebrates have an open circulatory system": This statement is not true. Vertebrates actually have a closed circulatory system, where blood is contained within vessels.

2. "All chordates have a closed circulatory system": This statement is also not true. While most chordates do have a closed circulatory system, there are some exceptions, such as the tunicates, which have an open circulatory system.

3. "All chordates are vertebrates": This statement is not true. Chordates include a wide range of animals, including vertebrates (animals with a backbone) and invertebrates (animals without a backbone), such as tunicates and lancelets.

4. "All vertebrates are chordates": This statement is true. Vertebrates are a subgroup of chordates, characterized by having a backbone or vertebral column.

Therefore, the correct statement among the given options is: "All vertebrates are chordates."