What is a diploid organism characterized by in terms of chromosome number?

A diploid organism is characterized by having two sets of chromosomes. This means that for each chromosome, there are two copies – one inherited from each parent. In humans and many other organisms, this results in a total of 46 chromosomes, organized into 23 pairs, with each pair consisting of one chromosome from the mother and one from the father.

This characteristic of diploidy is important because it allows for genetic diversity during reproduction. When gametes are formed through the process of meiosis, these diploid cells undergo division to produce haploid gametes, which contain only one set of chromosomes. The fusion of two haploid gametes during fertilization restores the diploid state in the zygote.

The other options describe conditions that do not apply to diploid organisms. For example, having only one set of chromosomes refers to haploid organisms, while possessing multiple sets of chromosomes is indicative of polyploidy, which is common in some plants. The absence of chromosomes would not apply to any living organism. Overall, the defining feature of diploid organisms is indeed their two sets of chromosomes, allowing for genetic variability and stability within a species.