Final answer:
Infecting snails is NOT part of the Ascaris lifecycle. Ascaris lifecycle's notable stages include the migration of larvae to the lungs and shedding of eggs in feces, following ingestion of contaminated food.
Step-by-step explanation:
The part of the Ascaris lifecycle that is NOT included is A) Infecting snails. The lifecycle of Ascaris does not involve snail hosts; rather, it includes entering the lungs via the bloodstream (B), being shed in feces (C), and entering the host via ingestion of food contaminated with dirt (D). Ascaris is a type of parasitic nematode whose eggs are ingested, hatch in the intestines, the larvae then migrate to the lungs and back to the throat to be swallowed again and mature in the intestines, with adults releasing eggs that exit the host through feces. This lifecycle is direct, meaning it does not require an intermediate host such as snails, which is characteristic of other parasites like Schistosoma species.