u r right about renal medulla and ur reason is right too.its just that all medulla's are not lighter than their corresponding cortex .

But my I was told that bi and di mean the same.
Could u please elaborate on this part.I really want this confusion to end once and for all.

.
that really helped
but that misspell was by mistake not on purpose.
thanks guys.

some say its riboluse biphosphate
and some say ribulose bisphosphate

active transport involves usage of ATP molecules \passive transport does not. active transport takes place against conc.gradient\it takes place along the gradient. mol. enter through spcl.pore on the cell membrane \mol. enter along with the water flow via endosmosis.

thanks but i found the answer after all.
1dna in i chromatin fibre.
i chromaton fibre in 1 chromosome.

hi guys,
i am a new comer could u pls help me out .i'm in a kind of a fix here
my zoology teacher asked that how many dna molecules does a chromatin fibre have and how many chromatin fibres make the chromosome structure with 4 chromatids???

pls help