Which phylum of animals lacks organ systems?

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:

Bilateral symmetry and acoelomate body organization are exhibited by which of the following?

Identify the Phylum $X$ based on the given flow chart.

Which specialised cells are present for excretion in the phylum $Platyhelminthes$?

Anus is absent in