Assertion : Bursa fabricii lies on the ventral side of the cloaca in birds.
Reason : Bursa fabricii is related with flight adaptation.

If both assertion and reason are true and reason is the correct explanation of assertion

If both assertion and reason are true but reason is not the correct explanation of assertion

If assertion is true but reason is false

If both assertion and reason are false

Solution

If both assertion and reason are false

In birds, the bursa of Fabricius is the site of Hematopoisis, a specialized organ that is necessary for B cell development in birds. Bursa is a small, glandular, blind pouch of lymphatic tissue present on the dorsal side of the cloaca. It is lined with endoderm, and opens into the proctodaeum.

In a young bird, bursa fabricii forms lymphocytes, and probably it produces antibodies and protects against local infection, but it atrophies in the adult before sexual maturity. It is also called cloacal thymus, because like thymus, it secretes lymphocytes. Thus, it is not related with flight adaptation, rather it helps in immunity.

Some More Questions From Evolution Chapter

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Evolution

Some More Questions From Evolution Chapter

What are the two key concepts of Darwinian Theory of Evolution

What were the units of life according to the early Greek thinkers ?

Mention the type of nutrition in the cells originated first during the origin of life.

Which group of organisms were responsible for appearance of free oxygen in the atmosphere of the primitive earth ?

What is meant by the term fossil ?

What is the type of evolution in which the same structure developed along different directions due to adaptations to different needs ?

Name the different eras of geologic time scale.

What is single step large mutation?

Consider a thorn in Bougainvillea and a tendril in cucurbita. Are these two organs homologous or analogous ? Give reason.

Give two examples that represent adaptive radiation.

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