Sum of twenty, use the numbers 0 - 9 so that each row column sum to 20. Diagonals are not included.

where each row and column sum up to 20

2    4    6    8  

4    2    6    8

6    6    4    4

8    8    4    0

Step-by-step explanation:

The sum of twenty using numbers 0 - 9

where each row and column sum up to 20

2    4    6    8  

4    2    6    8

6    6    4    4

8    8    4    0

when you sum up each of the row or each of the column the sum = 20

given that the diagonals are not included the sum of diagonals > or <  20

homozygous. one is homozygous, while two is heterozygous.