New species may be formed if
$(i)$ $DNA$ undergoes significant changes in germ cells
$(ii)$ chromosome number changes in the gamete
$(iii)$ there is no change in the genetic material
$(iv)$ mating does not take place

Which organism can change its sex?

$A$ cross between a tall plant $(TT)$ and a short pea plant $(tt)$ resulted in progeny that were all tall plants because

What is the genetic constitution of the $23$rd pair of sex chromosomes in a human female?

$A$ cross was carried out between a pure-bred tall pea plant and a pure-bred dwarf pea plant,and $F_{1}$ progeny was obtained. Later,the $F_{1}$ progeny was selfed to obtain $F_{2}$ progeny. Answer the following questions:
$(a)$ What is the phenotype of the $F_{1}$ progeny and why?
$(b)$ Give the phenotypic ratio of the $F_{2}$ progeny.
$(c)$ Why is the $F_{2}$ progeny different from the $F_{1}$ progeny?

What is the scientific name of the human species?