Question

Choose the correct answers from the alternatives given.
A shift from a reliance on .......... to reliance on .......... was pivotal in the evolution of all vertebrates:

• A. notochord; a backbone
• B. filter feeding; jaws
• C. gills; lungs
• D. all of these

Answer 1

The correct option is D all of these

A notochord is a primitive beginning to the backbone. It appears in embryos as a small flexible rod made from cells from the mesoderm, which is one of the three layers of cells of embryos. Notochords are only found in the phylum Chordata, a group of animals that includes humans. Filter feeders are animals that feed on particles or small organisms strained out of the water by circulating them through its system: includes most of the stationary feeders, like clams, oysters, barnacles, corals, sea squirts, and sponges. In addition, the derived character of upper jaw protrusion is acknowledged to increase the force exerted on the prey to be engulfed. The available evidence suggests that gills were present in the very earliest fishes, the common ancestor of hagfish and ray-finned fishes. However, lungs, gas-filled organs that serve the function of respiration, also evolved very early on.

So, the correct option is, 'all of these'.