What is the term for the number and type of chromosomes present in an organism?

The term that accurately describes the number and type of chromosomes present in an organism is "karyotype." A karyotype is a complete set of chromosomes in an individual, typically evaluated under a microscope to identify the number and structure of chromosomes. It provides a visual representation, usually arranged by size and shape, and is helpful for diagnosing genetic disorders, understanding species variations, and studying evolutionary relationships.

The other terms do not specifically refer to the chromosome composition. "Phenotype" refers to the observable traits of an organism, which can be influenced by both genetic and environmental factors. "Genotype" describes the specific genetic makeup of an organism, encompassing the alleles present for particular genes. "Homologous pair" refers to pairs of chromosomes that are similar in structure and genetic content, one inherited from each parent, but this term does not encompass the entire karyotype or its analysis. Thus, karyotype is the precise term for the complete set of chromosomes an organism possesses.