Final answer:
The salp oozoids of the species Praya dubia can form chains up to 50 meters long, and unlike other cnidarians, hydrozoans' gonads come from epidermal tissue.
Step-by-step explanation:
Salp oozoids, specifically from the species Praya dubia, have a really long chain of zoids, which can reach lengths of up to 50 meters (165 feet). Salps are part of the hydrozoan class, and one key feature they share with other hydrozoans is that their gonads are derived from epidermal tissue. This is in contrast to other cnidarians, where gonads come from gastrodermal tissue. This interesting attribute of hydrozoans distinguishes them from their cnidarian relatives, and underscores the diverse adaptations within the animal kingdom.