Sometimes the separation of twins is incomplete and these are borne attached are remain so even after. Such twins are known as
Fraternal
Dizygotic
Identical
Siamese
Extranuclear inheritance is a consequence of presence of genes in
$9 : 3 : 3 : 1$ ratio is modified to $9 : 7$ ratio due to
Mental retardation in man, associated with sex chromosomal abnormality is usually due to
Euphenics is
Mark the correct statement (w.r.t. sickle cell-anaemia)