Answer:
Down syndrome
Step-by-step explanation:
Down syndrome; is a condition in which there is an extra copy of a chromosome, total chromosomes are 47 (46+1). The patient of Down syndrome contain an extra copy of 21 th chromosome. Chromosome determine how a baby's body forms during pregnancy and how the baby's body functions as it grows in the womb and after birth. Typically, a baby is born with 46 chromosomes, but in case of down syndrome, there is an extra copy of 21 number chromosome, which cause greater risk of abnormality in fetus of aging oocyte.