In human beings, sex is determined by:

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

Study the following cross and the self-pollination in $F_1$. Fill in the blank and answer the question that follows:
Parents: $RRYY \times rryy$
(Round,yellow) (Wrinkled,green)
$F_1$: $RrYy \times$ ?
(Round,yellow)
What are the combinations of characters in the $F_2$ progeny? What are their ratios?

$(i)$ Name the scientist who proposed the theory of evolution of species by natural selection.
$(ii)$ What conclusion did Mendel draw from his experiments regarding traits?
$(iii)$ Arrange the following organisms in the order of their evolutionary complexity: Cockroach,Mango tree,Gorilla,Fish.

With the help of suitable examples,explain why certain traits cannot be passed on to the next generation. What are such traits called?

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