What is the difference between up-gradient and down-gradient?

In which process is oxygen absorbed by an organism asap apex

Neeed now for 1. eye color is a polygenic trait. what is the possibility of getting a green (aabb) eyed child, if parent 1 has brown eyes (aabb) parent 2 has blue eyes (aabb) 2.albinism is a recessive trait. having normal pigment is the dominant trait. what is the possibility of having an albino child if parent 1 is heterozygous normal parent 2 is heterozygous normal 3.in rabbits black fur is dominant over white fur. what is the probability of getting a rabbit with black fur if parent 1 is heterozygous black parent 2 is homozygous white

Abrown coat is recessive in labradors, while a black coat is dominant. if two hybrids are bred, what percentage of the offspring will have black coats? a. 25% b. 50% c. 75% d. 100%