Synergism.
Synergism happens when two or more chemicals enter the body and create adverse side effects/health concerns because of their use together. The effects of the two chemicals together is greater than the sum of the effects of the two individual chemicals.
A. Every biome that has living things.
Electricity could be discovered using batteries based on zinc or lead, but without copper wiring it would remain little more than a scientific curiosity. Electric motors and generators require large amount of wiring, so they are impossible to build on large scale in this world
When blood is in the lungs,
where oxygen is plentiful, oxygen easily binds to the first subunit and then quickly fills up the remaining ones. Then, as blood circulates through the body, the oxygen level drops while that of carbon dioxide increases. In this environment, hemoglobin releases its bound oxygen.
Natural selection is basically when organisms with the best traits survive and pass on their good traits to their offspring so that they will adapt easily and survive. Organisms who do not have ‘good traits’ that help them adapt and escape predators will be killed or eaten before they reproduce.
So in the end, natural selection is a form of evolution that allows the ‘fittest’ animals to survive and reproduce, while weeding out the unfit.