Question

While collecting specimens, a marine biologist finds a sessile Cnidarian. The medusas that bud from it swim by contracting a ring of muscle in their bells. To which class does this specimen belong?

a) Anthozoa
b) Hydrozoa
c) Scyphozoa
d) Cubozoa

Answer 1

The specimen found by the marine biologist, which is a sessile Cnidarian that releases swimming medusas, belongs to the class Hydrozoa.

Step-by-step explanation:

The marine biologist has discovered a sessile Cnidarian which forms medusas capable of swimming by contracting a muscular ring in their bells. The correct class for this specimen is Hydrozoa. The Anthozoa class, which includes sea anemones, corals, and sea pens, have only the polyp stage without a medusa stage. The Scyphozoa and Cubozoa classes include jellies with dominant medusa stages, but the specific characteristic of medusas having a velum, and Hydrozoa's tendency to have both polyp and medusa stages in their life cycle, along with the fact that gonads in Hydrozoa are derived from epidermal tissue, determines that the specimen in question belongs to Hydrozoa.