In a diploid set of chromosomes,the deletion or addition of a chromosome leads to:

Sometimes chromosome number increases or decreases due to:

What is Down's syndrome? Give its symptoms and cause. Why is it that the chances of having a child with Down's syndrome increase if the age of the mother exceeds forty years?

Which of the following disorders is seen in human females only?

What would be the number of chromosomes in the ovum (fertilized by a normal sperm) that resulted in the appearance of Klinefelter's syndrome in the offspring?

Mark the odd one with respect to the syndrome which occurs due to the failure of segregation of homologous pairs of chromosomes during the cell division cycle.