I am a bit confused on this question in my Textbook (STD 12) and have got all sorts of answers on searching it but I am still not able to comprehend it literally. Can someone answer this and explain when and where do the two type of segregation - A & B take place. I do know the how part.
Hmm, very cryptical formulations! I decided that B represents the chromosome because of "one pair" vs "independent pairs": All chromosomes are independent but many genes lie on the same chromosome and are therefore not independent, ignoring crossing-over for now.
It holds as well for the second statement, since it's the chromosomes that segregate, taking all genes that lie on them with them at the same time.
This NCERT question though... I guess they want us to take into account the phenomenon of linkage. If we do so, then genes on the same chromosome are not independent, but if they lie afar or lie on different chromosomes, then they can be said to be independent. Chromosomes have nothing as such and are always independent. Thus column A represents genes and column B represents chromosomes, the distinction made by the phrases "one pair" and "independent pair".