Identify the correct statement about vitamins and minerals: MCQ with Answer and Explanation

Explanation:
Down syndrome (trisomy 21) is an autosomal aneuploidy caused by nondisjunction resulting in three copies of chromosome 21. It is characterized by intellectual disability, flat facial profile, protruding tongue, and simian crease. Turner's syndrome is monosomy X (45, X). Klinefelter's is 47, XXY. Phenylketonuria is an inborn error of metabolism (autosomal recessive) due to deficiency of phenylalanine hydroxylase.

Explanation:
Double fertilization is a unique feature of angiosperms. One male gamete fuses with the egg cell to form the diploid zygote (syngamy), which develops into the embryo. The second male gamete fuses with the diploid secondary nucleus (polar nuclei) of the central cell to form the triploid Primary Endosperm Nucleus (PEN), which develops into the endosperm.

Explanation:
Polygenic inheritance is when multiple genes (polygenes) contribute to a single trait, resulting in continuous variation. Human skin color is controlled by at least three genes, showing a spectrum of phenotypes. Pleiotropy is one gene affecting multiple traits. Multiple alleles refer to more than two alleles for a gene (e.g., ABO blood groups). Co-dominance is when both alleles express equally.