Question

It's clearly mentioned in the NCERT , No viruses have both DNA and RNA but then why Leukovirus is an exception​ ??

Answer 1

Answer:

It depends on type of virus. Generally there are two kind of virus group viz. Retro-Virus , deoxyribovirus.

Retrovirus have RNA as genetic material while Deoxyribovirus have DNA as genetic material .

A virus can't have both RNA as well as DNA they either have DNA or RNA.

Explanation:

Answer 2

Answer:

See, there are so many cases in biology where are so many exceptions.

You are following NCERT, very good! But remember NCERT is just a High School textbook, behind which there is a whole world of exceptions and weird cases.

Let me tell you NCERT does not give pure full 100% correct information. This textbook has to be read what's its like. A few years ago, till 2016 or so, the DNA structure in XI textbook was wrong, and its was carried out for full 10 years! What I mean is we need to study this book just to qualify exams, and reach destination.

Another anecdote, Do you see the Euglena structure, in the same chapter, Biological classification? Boy, that's wrong too. This structure has been changed thrice, like my seniors say, and is still wrong.

You want another? In human physiology, there is a chapter neural control and coordination.

The brain stem is the whole blasphemy created by the marvelous NCERT itself. There is Three different definition in three different editions, so make sure you have the recent latest copy, or you are doomed.

..and about  Leukoviruses, they do have both, DNA and RNA. NCERT talks about IN GENERAL thingy.

..and there are more like the Foamy virus!

See, don't assume, the world ends with whats written in textbooks, the world is so vast that textbooks can never capture it all!

Its good to have knowledge, but for NEET, better cram and stick to your Bible, NCERT.

(You won't believe, I happened to go across the same dilemma!)

Go, get a latest copy.. if you don't want to get doomed.

EDIT;

a quote, by Albert Einstein may highlight the idea!

"The most comprehensible thing about the world is that, its is incomprehensible"