From the list given below,select the character which can be acquired but not inherited.

Where are the genes located? What is the chemical nature of a gene?

The genotype of a green-stemmed tomato plant is denoted as $GG$ and that of a purple-stemmed tomato plant as $gg$. When these two are crossed:
$(i)$ What colour of stem would you expect in their $F_1$ progeny?
$(ii)$ Give the percentage of purple-stemmed plants if $F_1$ plants are self-pollinated.
$(iii)$ In what ratio would you find the genotypes $GG$ and $Gg$ in the $F_2$ progeny?

Why do all the gametes formed in human females have an $X$ chromosome?

What evidences can suggest that, "Modern human beings have originated in Africa"?

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