; (7) alternatives to nonhuman primate research such as organs-on-chips technology and computer modeling are now available; and (8) nonhuman primates should only be used in research to fulfill an important public health objective and if no alternative research method exists. 3. Definitions In this Act: (1) Active protocol The term active protocol means a valid, non-expired experimental plan approved by the animal use committee of a research institution. (2) Ethologically appropriate environment The term ethologically appropriate environment means a set of species-specific standards for the living conditions for captive nonhuman primates that— (A) is informed by scientific evidence and expertise from animal behaviorists; (B) promotes the full range of the natural cognitive abilities of the nonhuman primate, including healthy outlets to fulfill needs for inquisitiveness and inventiveness; (C) comports with the natural social arrangements of the nonhuman primate as observed in the wild, including the preservation of healthy maternal relationships, familial groups, colonies, and pair-bonds; (D) consists of a secure, contained physical habitat that, at a minimum— (i) is sufficiently complex and appropriately sized so that the inhabitants can establish and maintain stable dominance hierarchies, including the provision of secluded areas for submissive individuals to escape or hide from aggressors; (ii) has access to the outdoors with complex, natural features and substrates, such as grass, dirt, mulch, and vegetation; (iii) provides foraging opportunities and diets that are varied, nutritious, and challenging to obtain; and (iv) includes not fewer than 1 climbing structure of sufficient height and complexity such that multiple individuals can climb or descend at the same time, with the ability to rest on separate tiers