Every cell<span> in your body contains organelles (structures that have specific functions). Just like organs in the body, each </span>organelle<span> contributes in its own way to helping the cell function well as a whole. The </span>nucleus<span>, </span>mitochondria<span> and </span>chloroplasts<span> are all organelles.</span>
Well it's thought that the oxygenation of the atmosphere contributed to the evolution
Dominant refers to the relationship between two versions of a gene. Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed; it is the dominant gene. The effect of the other allele, called recessive, is masked.
