While sampling marine plankton in a lab, the student encounters fertilized eggs and decides to hatch them in the lab. the student observes that the blastopore develops into the mouth. they also notice on further development that the animal has an 8-plated shell and a radula.
these eggs most likely belong to a/an

a) mollusc.
b) echinoderm.
c) nematode.
d) arthropod.

A) mollusc.

Explanation:

Molluscs are soft-bodied animals often covered by a 8-plated shell.

During embryonic development blastopore becomes mouth in protostomes and mollusks are protostomes.

In mollusks such as snail, sepia radula are present. Radula have row of teeth consists of marginal teeth, lateral teeth and a median tooth and are used to peel off plant parts during feeding. They also used to scrape rocks to make depression in rocks for their habitats.  

allowed for the prediction of the properties of missing elements.

voluntary muscles are controlled by the cerebellum.