What type of organism does the term 'arthropod' refer to?

The term 'arthropod' specifically refers to organisms characterized by having jointed appendages and an external skeleton, known as an exoskeleton. This group includes a vast variety of animals such as insects, arachnids (spiders and scorpions), crustaceans (crabs and lobsters), and myriapods (centipedes and millipedes). The jointed appendages allow for a range of movements that are essential for mobility and interaction with their environment. The exoskeleton serves multiple functions, including providing structural support, protection against physical damage, and resistance to desiccation. This unique combination of features is what distinguishes arthropods from other types of organisms, making option B the correct choice.