Which one of the following exhibits concentric tube within tube plan ?

Which one of the following exhibits concetric "tube within tube" plan

Which one exhibits concentric tube-within-tube plan ?

Which one exhibits concentric tube-within-tube plan ? (a) Arthropoda (b) Oligochaeta /Earthworm (c) Mollusca (d) Echinodermata

Which one exhibits concentric tube-within-tube plan ? (a) Arthropoda (b) Oligochaeta /Earthworm (c) Mollusca (d) Echinodermata

Which of the following has pseudocoelomate tube within a tube body plan

Which one forms the pollen tube

Which one forms the pollen tube

Which of the following animals has tube- within-tube type of body plan evolved along deuterostomic evolutionary line ?

Which of the following animals has tube- within-tube type of body plan evolved along deuterostomic evolutionary line ?