Which of the following is not a sex-linked trait?

Which of the following statements are incorrect? $(i)$ $ABO$ blood grouping is controlled by gene $I$. (ii) Gene $I$ has four alleles. (iii) $I^A$ and $I^B$ produce the same type of sugar. (iv) $I$ or $i$ produces a different type of sugar. $(v)$ $I^A$ and $I^B$ are incompletely dominant.

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

Which of the following is a placental mammal and not a marsupial?

Which mammals have more yolk than cytoplasm in their eggs?

$A$ back-cross is a cross between ........