Lifespan of Ascaris is
A. 3 to six months
B. 9 to 12 months
C. 1 year
D. 2 to five months

Hint: Ascaris is the genus of parasitic nematode worms referred to as small intestinal roundworms which may be a sort of parasitic worm. One species that affects the citizenry is the common roundworm which causes the disease name of ascariasis.

Complete answer:
Life cycle of Ascaris- or common roundworm
- Adult worms sleep in the lumen of the tiny intestine. A female may produce up to 240,000 eggs per day, which are passed with the feces.
- Fertile eggs embryonated and become ineffective after 18 days to many weeks, counting on the environmental conditions (favourable conditions:moist, warm, shaded soil) .
- After infective eggs are swallowed by human beings through contaminated food water or by touching your mouth with dirty hands etc then the larvae hatch, invade the intestinal mucosa, and are carried via the portal, then circulation to the lungs. The larvae mature further within the lungs (10-14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed. Upon reaching the tiny intestine, they become adult worms.
- Between two and three months are required from ingestion of the infective eggs to oviposition by the woman.
- Therefore the lifespan of infectious sort of ascaris is 9-12 months.

Let us look at the given options:
> Option A- 3 to six months
This is the incorrect answer as ascaris needs less time to become infective.

> Option B-9 to 12 months
Ascaris belongs to Nematoda. These are roundworms. They're triploblastic and pseudocoelomate. They need a lifespan of 9 to 12 months within the host body. It causes the disease referred to as ascariasis.

> Option C 1 to 2 year
Adult worms can live for 1-2 year but outside the physical body as within the soil. So this is not an accurate option.

> Option D 2 to five months
Ascaris need time between 2 and 5 months are required from ingestion of the infective eggs to oviposition by the woman. So this is also a wrong answer.

Hence, the correct answer is option (B).

Note: A roundworm called common roundworm infects a person’s intestine and acts as a parasite, getting nutrients from its host’s intestinal tract. Ascaris lumbricoides, along with hookworm, may be a sort of parasite referred to as a soil-transmitted helminth (STH).