Answer: alleles
Explanation:
"An allele is a variant form of a gene. Genes come in different varieties, called alleles. Somatic cells contain two alleles for every gene, with one allele provided by each parent of an organism."- Nature .com
Of lower concentration and higher concentration
Answer:
A. aneuploidy; trisomic
Explanation:
Aneuploidy means having more numbers of chromosomes than usual while polyploidy means having an abnormal number of chromosome sets. Down syndrome is a trisomy on chromosome 21 meaning there are 3 chromosomes for chromosome set 21.