How does inheritance of one Gene take place ?

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 do not shows its effects when paired with a dominant allele

$IV.$ A dominant allele is always better for an organism

Definitions / Explanation : Dominant gene & Recessive gene.
 

Define and design a test – cross?

Mendel’s law of independent assortment is applicable for