Final answer:
Human somatic cells have 23 pairs of chromosomes, with the 23rd pair being the sex chromosomes. The chromosomes can be arranged in a karyotype according to their length. Each pair of chromosomes consists of homologous chromosomes that contain the same genes but different alleles.
Step-by-step explanation:
In human somatic cells, there are 23 pairs of chromosomes. These chromosomes are viewed within the nucleus and can be arranged according to their length in an arrangement called a karyotype.
Each pair of chromosomes consists of homologous chromosomes, which are chromosomes that are similar in size and shape and contain the same genes but different alleles. The 23rd pair of chromosomes is the sex chromosomes, and in females, it consists of two X chromosomes.