Question

20. Which of the following statements is/are correct?

A. Molluscs can live in marine, and freshwater habitats but do not live in terrestrial habitats.

B. Given the following on the organism:

I. An animal

II. Multicellular

III. has tissues

IV. has a digestive tract

V. exhibits bilaterally symmetry as an adult

This organism could be a member of the Phylum Mollusca

C. Molluscs can produce a shell and the presence of a shell at one point in development is a requirement for inclusion into this phylum.

D. Lobsters are members of the phylum Mollusca

E. Molluscs have three main body parts, a muscular foot, a visceral mass, and a head

Answer 1

ANSWER;----

A. MOLLUSCS CAN LIVE IN MARINE ,AND FRESHWATER HABITATS BUT DO NOT LIVE IN TERRESTRIAL HABITATS.

ANSWER - THIS IS WRONG STATEMENT ,BECAUSE MOLLUSCS OCCUPY ALL THE POSSIBLE HABITAT EXCEPT AERIAL,THEY FOUND IN MARINE WATER ,FRESH WATER AS WELL AS IN TERRESTRIAL.

SO OPTION A IS WRONG

B. FROM GIVEN STATEMENT IT IS CLEAR THAT GIVEN ORGANISM IS FROM PHYLUM MOLLUSCA BECAUSE ,

1 - AN ANIMAL- YES IT IS AN ANIMAL   2-MULTICELLULAR - YES IT IS MOLLUSCS ARE MULTI CELLULAR 3- HAS A TISSUE --- YES MOLLUSCS HAD 4- HAS A DIGESTIVE TRACT - YES MOLLUSCS HAVE DIGESTIVE TRACT .THE DIGESTIVE TRACT IN MOLLUSCA IS COMPLETE.THERE IS A GLAND WHICH HELP IN SECRETION OF DIGESTIVE JUICES IS HEPATO-PANCREASE. BUCCAL CAVITY OFTEN HAVE A RASPING ORGAN KNOWN AS RADULA. 5- EXHIBIT BILATERAL SYMMETRY AS AN ADULT -- YES IT MOLLUSCA HAVE BILATERAL SYMMETRY.

SO AS WE SEE ABOVE ALL FIVE CHARACTER EXHIBIT BY MOLLUSCS ,SO GIVEN ORGANISM IS FROM PHYLUM MOLLUSCA.

SO OPTION B IS CORRECT.

C. MOLLUSCS CAN PRODUCE A SHELL AND THE PRESENCE OF A SHELL AT ONE POINT IN DEVELOPMENT IS A INCLUSION INTO THIS PHYLUM. ANSWER --- SOME MOLLUSCS HAD SHELL BUT SOME MOLLUSCS DO NOT POSSES SHELL, SO IT IS NOT MANDATORY TO BE A MEMBER OF MOLLUSCS ,ORGANISM SHOULD HAVR SHELL. SHELL IS NOT PRESENT IN ALL MOLLUSCS. SHELL IS MAY BE PRESENT OR MAY NOT BE PRESENT. SHELL IS SECRETED BY MANTLE. IT IS CALCAREOUS.THE MANTLE USUALLY SECRETS A EXTERNAL SLIMY SHELL, SHELL MAY BE INTERNAL (CUTTLE FISH),REDUCED AND ABSENT (OCTOPUS)

SO OPTION C IS NOT CORRECT.

D. LOBSTERS ARE MEMBER OF PHYLUM MOLUSCA - ANSWER-- LOBSTERS SRE NOT MEMBER OF MOLLUSCA ,THEY ARE MEMBEROF PHYLUM ORTHROPODA.

SO OPTION D IS WRONG.

E. MOLLUSCS HAVE THREE MAIN BODY PARTS , A MUSCULAR FOOT ,A VISCERAL; MASS,AND A HEAD. ANSWER--- YES IT IS CORRECT, MOLLUSCS HAVE THREE DIFFERENT BODY PART -- A ANTERIOR HEAD WITH SENSE ORGANS. DORSAL VISCERAL MASS CONTAINING ORGAN SYSTEMS. VENTRAL MUSCULAR FOOT FOR LOCOMOTION

SO OPTION IS CORRECT.