Answer:
The answer is A, open systems!!
Explanation:
all systems on earth are open, except for the earth itself.
If we cross a homozygous blue oval plant with a homozygous white round plant
P: BBrr x bbRR
The resulting F1 progeny:
F1: BbRr
If we cross BbRr with bbrr
F2: 1/4 blue round plants (250 plants) ¼ blue oval plants (250 plants) ¼ white round plants (250 plants) and ¼ white oval plants (250 plants).
Natural selection would be the correct answer
This means that each dominant allele "adds" to the expression of the next dominant allele. Usually, traits are polygenic when there is wide variation in the trait. For example, humans can be many different sizes. Height is a polygenic trait, controlled by at least three genes with six alleles.