Answer: 50%.
Explanation:
The A allele, which corresponds to red flowers is dominant, meaning if one is present, the flower is red. This generates Aa, which matches 2 squares, denoting a 50% in 4 total boxes. The a allele, corresponds to green flowers but is recessive, meaning both alleles must correspond to said trait to be expressed. 2 squares fit this scenario, making another 50% chance. Therefore, the answer would be 50%.
