For completing its life cycle, Tapeworm requires/ Intermediate host of Tapeworm is

Which of the following phyla has an incomplete digestive tract?

All flatworms differ from all roundworms in having

Given below are two statements.
Statement $I$: Cephalic ganglion appears like $U$ shaped structure in Hydra.
Statement $II$: Ventral nerve cords are connected to each other by commissure in a ladder like manner in Planarian.
In the light of above statements,choose the most appropriate answer from the options given below:

Which of the following is a free-living flatworm?

Which phylum of animals lacks organ systems?