Which gene is lethal in maize?

Which of the following characteristics represent 'Inheritance of blood groups' in humans?
$(a)$ Dominance
$(b)$ Co-dominance
$(c)$ Multiple allele
$(d)$ Incomplete dominance
$(e)$ Polygenic inheritance

Match List $I$ with List $II$:

List $I$	List $II$
$A$. Two or more alternative forms of a gene	$I$. Backcross
$B$. Cross of $F_1$ progeny with homozygous recessive parents	$II$. Ploidy
$C$. Cross of $F_1$ progeny with any of the parents	$III$. Allele
$D$. Number of chromosome sets in plant	$IV$. Test cross

Choose the correct answer from the options given below:

Give differences: Incomplete dominance and Co-dominance.

Hybrid vigour is due to

In a dihybrid cross,when one pair of alleles shows incomplete dominance,the resulting genotypic ratio will be ....