The life span of $Ascaris$ is:

Which of the following is another characteristic of the animal group that first possesses a complete digestive system?

$A$ rhabditiform larva is formed in the life cycle of

Ancylostoma,also known as $.....(A).....$,belongs to the phylum $.....(B)....$. Identify $A$ and $B$ respectively and choose the correct option.

Which of the following animals possesses a pseudocoelom?

Cyclops is the intermediate host of: