Given the question: Information: - In botany, succulent plants, also known as succulents or sometimes fat plants, are plants that have some parts that are more than normally thickened and fleshy, usually to retain water in arid climates or soil conditions. The word "succulent" comes from the Latin word "sucus", meaning juice, or sap. Succulent plants may store water in various structures, such as leaves and stems. Some definitions also include roots, so that geophytes that survive unfavorable periods by dying back to underground storage organs may be regarded as succulents. In horticultural use, the term "succulent" is often used in a way which excludes plants that botanists would regard as succulents, such as cacti. Succulents are often grown as ornamental plants because of their striking and unusual appearance. - Crassula falcata , known by the common names airplane plant and propeller plant , is a succulent plant endemic to South Africa , from the Cape of Good Hope . The foliage is gray - green with striking texture , on plants that grow to 2 feet ( 0.61 m ) tall . The flowers are tiny and scarlet red , that rise in dense clusters above the foliage for a month in summer . Crassula falcata is cultivated for use in drought tolerant and succulent gardens , and in container gardens . - South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded on the south by of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans, on the north by the neighbouring countries of Namibia, Botswana and Zimbabwe, and on the east and northeast by Mozambique and Swaziland, and surrounding the kingdom of Lesotho. South Africa is the 25th-largest country in the world by land area, and with close to 56 million people, is the world's 24th-most populous nation. It is the southernmost country on the mainland of the Old World or the Eastern Hemisphere. It is the only country that borders both the Atlantic Ocean and the Indian Ocean. About 80 percent of South Africans are of Sub-Saharan African ancestry, divided among a variety of ethnic groups speaking different Bantu languages, nine of which have official status. The remaining population consists of Africa's largest communities of European (white), Asian (Indian), and multiracial (coloured) ancestry. - Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as houseplants, for cut flowers and specimen display. The cultivation of these, called floriculture, forms a major branch of horticulture. - A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkir plant life-form classification system. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions (such as cold, excessive heat, lack of light or drought). - Swaziland, officially the Kingdom of Swaziland (or ; Swazi: "Umbuso weSwatini"; sometimes called kaNgwane or Eswatini), is a sovereign state in Southern Africa. It is neighboured by Mozambique to its northeast and by South Africa to its north, west and south. The country and its people take their names from Mswati II, the 19th-century king under whose rule Swazi territory was expanded and unified. - Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. - Botany, also called plant science(s), plant biology or phytology, is the science of plant life and a branch of biology. A botanist or plant scientist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word ("botan") meaning "pasture", "grass", or "fodder"; is in turn derived from ("boskein"), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists study approximately 400,000 species of living organisms of which some 260,000 species are vascular plants and about 248,000 are flowering plants. - Lesotho, officially the Kingdom of Lesotho, is an enclaved, landlocked country in southern Africa completely surrounded by South Africa. It is just over in size and has a population slightly over two million. Its capital and largest city is Maseru. - The Bantu languages, technically the Narrow Bantu languages (as opposed to "Wide Bantu", a loosely defined categorization which includes other Bantoid languages), constitute a traditional branch of the NigerCongo languages. There are about 250 Bantu languages by the criterion of mutual intelligibility, though the distinction between language and dialect is often unclear, and "Ethnologue" counts 535 languages. Bantu languages are spoken largely east and south of present-day Cameroon, that is, in the regions commonly known as Central Africa, Southeast Africa, and Southern Africa. Parts of the Bantu area include languages from other language families (see map). After reading the paragraphs above, we are interested in knowing the entity with which 'crassula falcata' exhibits the relationship of 'taxon rank'. Find the answer from the choices below. Choices: - branch - form - kingdom - species - variety
The answer is:
variety