Hello.
There are a couple things needed for natural selection.
Natural selection is organisms become comfortable and changer where they are newly located. Where they can live and get more off springs.
First, You will need <u>heredity</u> which passes traits to an offspring.
Second, <u>reproduction</u> that is needed to to copy traits and give them to the offspring.
A gene is a hereditary trait in your body and also apart of your DNA not visible to the naked eye making up how you look
A dog breathes in oxygen and then releases carbon dioxide when he exhales. Conversely, a tree gives off oxygen and takes in carbon dioxide. So the breath of the dog sustains the tree while the output of oxygen for the tree sustains the dog.
