Although a phenotype is the ensemble of observable characteristics displayed by an organism, the word "phenome" is sometimes used to refer to a collection of traits, while the simultaneous study of such a collection is referred to as "phenomics". Phenomics is an important field of study because it can be used to figure out which genomic variants affect phenotypes which then can be used to explain things like health, disease, and evolutionary fitness. Phenomics forms a large part of the Human Genome Project