A pedigree chart below shows the inheritance of a particular sex-linked trait ("trait") Key: Unaffected Males Affected Males Unaffected Females Affected Females How is the trait being studied in the pedigree chart above?
Dominant $X$-linked
Recessive $X$-linked
Dominant $Y$-linked
Recessive $Y$-linked
Who discovered $R{h^ - }$ factor
Lethal genes are
Mental retardation in man, associated with sex chromosomal abnormality is usually due to
Self sterility in "Nicotiana'' was reported by
Frequency of Down’s syndrome increases when the maternal age is