an excellent source of protein to the ancient Mesoamericans, as well as to people today. Another major food source in Mesoamerica are beans. Maize, beans, and squash form a triad of products, commonly referred to as the "Three Sisters". Growing these three crops together helps to retain nutrients in the soil. Rubber trees and cotton plants were useful for making culturally significant products such as rubber balls for Mesoamerican ball games and textiles, respectively. Evidence of these ball games is found throughout Mesoamerica, and the performance of these games is related to many origin myths of the Mesoamerican people. The game had a ritualistic significance and was often accompanied with human sacrifice. The domestication of cotton allowed for textiles of vibrant colors to be created. These textiles are evidence of the Mesoamerican peoples' fascination with adornment and the cultural value they placed on appearance. Another culturally important plant was cacao (ancient Mesoamerican chocolate). Cacao was used in rituals (as a drink) and was also used as currency in trade. The crops above are only a few of the domesticated plants important to the ancient peoples of Mesoamerica. Please see the section below for a more comprehensive list of ancient Mesoamerican domesticated plants. Domestic plants Main source: Pre-Columbian Foodways A list of Mesoamerican cultivars and staples: Agave* – also known as the "century plant" Anona – also called a "custard apple" Avocado* – large, green, egg-shaped berry with a single seed Cacao* – the main ingredient in chocolate Cassava* – edible starchy root also known as manioc; also used to make tapioca Chaya – large fast-growing leafy shrub with uses similar to spinach Cherimoya* (fruit) Chicle* (Manilkara chicle) – sap made into chewing gum Chili peppers* – many varieties Copal – incense used by the Maya for religious practices Cotton* – a shrub that is used mainly to create textiles Epazote (Dysphania ambrosioides) – aromatic herb Guayaba* – guava fruit Huautli* (Amaranthus cruentus, Amaranthus hypochondriacus) – grain Jícama* (Pachyrhizus erosus) Maize* – domesticated from teosinte grasses in southern Mexico) Mamey sapote* (Pouteria sapota) – fruit, other parts of plants have noted uses Mora (Rubus blackberry) Nopales* – stem segments of Opuntia species, such as Opuntia ficus-indica Papaya* (Carica papaya) Pineapple – cultivated extensively Pinto bean – "painted/speckled" bean; nitrogen-fixer traditionally planted in conjunction with the "two sisters", maize and squash, to help condition soil; runners grew on maize Squash* (Cucurbita spp.)