Dihybrid cross is a cross between two different lines/genes that differ in two observed traits. According to Mendel's statement, between the alleles of both these loci there is a relationship of completely dominant - recessive traits. 

What is a Dihybrid Cross?
A dihybrid cross is a genetic cross between two individuals that differ in two traits. This type of cross helps to understand the inheritance pattern of two different traits simultaneously.

Explanation in Detail
- In a dihybrid cross, the Punnett square is used to predict the possible genotype combinations in the offspring.
- Each parent is heterozygous for both traits, resulting in a 4x4 Punnett square.
- The alleles for each trait segregate independently during gamete formation, leading to different combinations of traits in the offspring.
- The phenotypic ratio in the offspring is typically 9:3:3:1, representing the different possible combinations of traits.

Board Paper Of Class 10 2019 Science Delhi(Set - 1)
In the Class 10 Science Board Paper of 2019 for Delhi, students may have encountered questions related to genetic crosses, including dihybrid crosses. It is important for students to understand the concepts of genetic inheritance and how to solve problems related to dihybrid crosses.