How many pairs of chromosomes are present in human beings (in $pairs$)?

$(a)$ Distinguish between homologous and analogous organs.
$(b)$ State one evidence of organic evolution.

The two versions of a trait (character) which are brought in by the male and female gametes are situated on

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?

If the fossil of an organism is found in the deeper layers of the Earth,then we can predict that:

What are the basic features of the mechanism of inheritance?