Give the pair of contrasting traits for the following characters in a pea plant and mention which is dominant and which is recessive:
$(i)$ Yellow seed
$(ii)$ Round seed

An angiosperm plant having red coloured flowers when crossed with another having the same colour produced $40$ progenies,out of which $30$ plants were with red coloured flowers and $10$ plants were with white coloured flowers. Find out:
$(a)$ What is the possible genotype of parent plants?
$(b)$ Which trait is dominant and which is recessive?
$(c)$ What is this cross called and what is its phenotypic ratio?

$(a)$ "Each organism has its own identity". Explain.
$(b)$ What is speciation?

When a sperm carrying an $X$ chromosome fertilizes an ovum,what will be the sex of the embryo that develops from the zygote?

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

$(a)$ What are fossils?
$(b)$ Explain the importance of fossils in evolutionary relationships.