The important and universal phenomenon of life, "$Like\, begets\, like$", is due to .....

Based on Mendel's experiments,explain the concepts of factors,dominant/recessive traits,genotype,and phenotype.

Choose the incorrect pair for the characters studied by Mendel.

$A$: Mendel proposed postulates like "principles of segregation and principles of independent assortment" after studying seven pairs of contrasting traits in garden pea.
$R$: He was lucky in selecting seven characters in pea that were located on seven different chromosomes.

How many pairs of contrasting traits were selected by Mendel for his study on garden peas?

Mendel selected ....... true-breeding pea plant varieties.