Question

what difference do u find in the presence and the number of chromosomes in 18 years young man and 8months baby?

Answer 1

In humans, each cell normally contains 23 pairs
of chromosomes, for a total of 46. Twenty-two
of these pairs, called autosomes, look the same
in both males and females. The 23rd pair, the
sex chromosomes, differ between males and
females. Females have two copies of the X
chromosome, while males have one X and one
Y chromosome.
So, no matter whai is the age of person.. the no. of chromosomes are always the same i.e. 46(23 pair)...... But sometimes an error occurs when the 46
chromosomes are being divided in half. An
egg or sperm cell may keep both copies of
chromosome number 21, instead of just 1
copy. If this egg or sperm is fertilized, then
the baby will have 3 copies of chromosome
number 21. This is called trisomy 21.