Question

In Bonellia , all larvae are genetically and cytologically similar. In this worm, male individuals live in the uterus of females. In a particular lava settle near the proboscis of an adult female, it becomes a male individual. If larva develops free in water it becomes
(a) Male individual
(b) Female individual
(c) Intersex
(d) All of the above

Answer 1

We can not isolate the developing embryo from its environment as it plays a very important role in the development of the organism it is mentioned here that males develop by settling near the proboscis of the adult females.

Complete answer:
In Borrelia, if the larva develops free in water it becomes female individuals. Bonellia is also known as echiuroid worm. The sex of the Bonellia depended upon the area where the Bonellia larva settled.
If a Bonellia larva settles on the floor of the sea, it develops into a female.

Additional Information:
-To understand the developmental mechanisms we have to consider the temperature and media in which embryos were developing.
-All the larvae of Bonellia are identical genetically.
-The female Bonellia worm is a rock-dwelling marine animal.
-The body of the female worm is about 10 cm long but tits proboscis can extend up to a meter in length.
-If a larva lands on a female's proboscis it enters the female's mouth and migrates into her uterus, and differentiates into a male.
-The male Bonellia is only 1–3 mm long and resides within the uterus of the female, there it is fertilizing the female’s eggs.
-When the partly developed males get detached from the female body leads to its development into an intersex worm.
So, the correct answer is,’ Female individual’.

Note:
-In Bonellia sex determination is governed by environmental factors.
-The larva settles on the floor of the sea and develops into a female.
-The larva enters the female body through the mouth and resides in the uterus and develops into a male individual.