The first definite proof of mutagenic action of $X$-rays was given by
Muller
Hooker
Lister
Leeuwenhoek
A recessive gene is one which
Which one of the following is a dominant trait
If in a child of $10$ years ages of the intelligence is of $14$ years child, the $I.Q.$ of this child would be
Improvement of human race through hereditary qualities is called
When closely placed genes on the same chromosome are inherited together the phenomenon is known as