Which of the following symbols and its representation is correctly used for constructing a human pedigree chart?

Choose the correct sequence of True $(T)$ and False $(F)$ statements:
$(i)$ Queen Elizabeth shows a number of haemophilic descendants.
$(ii)$ Variation in blood group prevalences is due to incomplete dominance.
$(iii)$ Drosophila has three pairs of autosomal chromosomes.
$(iv)$ In birds,the female is heterozygous.

Which of the following pairs is $wrongly$ matched?

In certain plant species,red flower colour is incompletely dominant to white flower colour (the heterozygote is pink) and tall stems are completely dominant to dwarf stems. If a tall pink plant $(TtRr)$ is crossed with a tall white plant $(TTrr),$ which one of the following types of plants would be produced in the offspring?

In a diploid organism,the condition where one of the alleles in a pair is present is called.....

It is said that harmful alleles are eliminated from a population over a period of time,yet sickle cell anaemia persists in the human population. Why?