Explanation: Scientists believe the increased risk is due to the extra chromosome, chromosome 21, that causes Down syndrome. Persons born with Down syndrome have three copies (instead of the normal two copies) of this chromosome.
Answer:
do it yourself
Explanation:
숨을 들이쉴 때마다 폐포가 공기로 채워져 폐가 확장됩니다.
도움이 되기를 바랍니다 !!
long cold winters, with annual temperatures mostly below freezing.
i think that -5 will be the answer
