When we breathe, our respiratory system takes up oxygen and carbon dioxide or other useless gases go out . The oxygen combines with the haemoglobin in the blood of the circulatory system . This is transferred to all the cells of our body to get energy.
Natural selection is where positive traits survive more, allowing those to become more common. Mutation is where radioactivity changes genes in a random way. Natural selection allows positive mutation to become more common. Adaptation is where natural selection works for a species specifically more a new habitat.
C. Law of segregation is the Mendel's law that states that gametes carry one allele for each trait.
Sexual reproduction results diversity