How many types of zygotic combinations are possible between a cross $Aa \; BB \; Cc \; Dd \times AA \; bb \; Cc \; DD$?

$A$ : Test cross is the tool for knowing linkage between genes.
$R$ : Monohybrid test cross gives two phenotypes and two genotypes.

Which of the following statements is correct?

Match List-$I$ with List-$II$ :

List-$I$ (Type of Inheritance)	List-$II$ (Example)
$A$. Incomplete dominance	$I$. Blood groups in human
$B$. Co-dominance	$II$. Flower colour in Antirrhinum
$C$. Pleiotropy	$III$. Skin colour in human
$D$. Polygenic inheritance	$IV$. Phenylketonuria

Choose the correct answer from the options given below :

The presence of four horns instead of two in a goat is an example of what?

Which of the following statements are false?
$I.$ $A$ dominant allele determines the phenotype when paired with a recessive allele.
$II.$ $A$ recessive allele is weaker than a dominant allele.
$III.$ $A$ recessive allele does not show its effects when paired with a dominant allele.
$IV.$ $A$ dominant allele is always better for an organism.