Which of the following animals possesses an incomplete digestive system (lacking an anus)?

Both alternation of generations and alternation of hosts are present in

The human liver fluke depends on how many intermediate hosts to complete its life cycle?

Which of the following groups is consistent?

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:

What is the covering present around the body of parasitic animals belonging to the phyla Platyhelminthes and Nematoda?