Animal having a single opening to the outside that serves both as mouth as well as anus is:

Options

(a) Octopus
(b) Asterias
(c) Ascidia
(d) Fasciola

Correct Answer:

Fasciola

Explanation:

Fasciola, a flatworm has a single body cavity to the outside that serves both as mouth for ingestion and anus for egestion of undigested food. This is known as blind sac plan.