While sampling marine plankton in a lab, a student encounters large numbers of fertilized eggs. The student rears some of the eggs in the laboratory for further study and finds that the blastopore becomes the mouth. The embryo develops into a trochophore larva and eventually has a true coelom. These eggs probably belonged to a(n) .A. chordate. B. echinoderm. C. mollusc. D. nematode. E. arthropod.

Mollusc

Explanation: Mollscs are the next biggest phylum of animals that do not have nor develop backbone which includes nearly 23% of every named individual being that embodies the properties of existence in the sea. However, they live in both flowing water like streams and springs and in still water like ponds and lakes, some also live on land. They are highly different in both in size and structure and in attitude and environment.

cats ; snakes

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.