What are the reasons for Mendel's successes in his breeding experiments?

Explanation

(i) He applied mathematics and statistical methods to biology and laws of probability to his breeding experiments.
(ii) He followed scientific methods and kept accurate and detailed records that include quantitative data of the outcome of his crosses.
(iii) His experiments were carefully planned and he used large samples.
(iv) The pairs of contrasting characters which were controlled by factor (genes) were present on separate chromosomes.
(v) The parents selected by Mendel were pure breed lines and the purity was tested by self crossing the progeny for many generations.