contributions of gregor mendel in the field of biology. (brief)

Gregor J. Mendel, also known as the father of genetics has many contributions towards the field of genetics. His contributions are as follows:

1) He gave the concept of factors or alleles for a trait. He said that every organism has two factors for a trait, one received from each parent. 

2) Law of dominance: It states that there are two types of factors or alleles for a gene, dominant and recessive. The Factor which expresses itself in heterozygous condition is the dominant factor; while, the other one is recessive.

3) Law of segregation: It states that during gamete formation, the factors for a trait are separated from each other. At the time of fertilization, they unite randomly.  

4) Law of independent assortment: It states that during gamete formation, the factors for different traits segregate independent of each other.