What must be done to breed dogs for a particular trait? a. mate two dogs that have the desired trait. b. protect dogs with the trait from natural selection. c. mate any dogs and see what variations occur. d. place dogs in places where they can acquire the trait.

Red blood cells are responsible for transporting oxygen in the blood. people with sickle cell anemia were born with a defective gene that results in sickle-shaped red blood cells. individuals with the disease often suffer pain in their extremities due to the build-up of these cells causing blockages in the blood vessels. the shape of the blood cells also reduces the amount of oxygen transported in the blood.