a living thing; anything that can carry out life processes independently
Organism
the mainly underground organ of vascular plants that holds plants in place and absorbs and stores water and minerals from the soil
roots
an action that an individual carries out in response to a stimulus or to the environment
behavior
the body system made up of the heart, of the blood vessels, and of the blood
circulatory system
what receptors detect pressure, movement, and tension?
mechanical receptors
a group of similar cells that perform a common function
tissue
a plant structure that provides support and transports nutrients
stems
the ability to store and recall past experience
memory
the organ system whose primary function is movement and flexibility
muscular system
what receptors detect chemical signals such as odors and tastes.
chemical receptors
a collection of tissues that carry out a specialized function of the body
organ
A change in the direction of plant growth in response to gravity
Geotropism
the organs that break down food so that it can be used by the body
digestive system
the structures that control the actions and reactions of the body in response to stimuli from the environment; it is formed by billions of specialized nerve cells, called neurons
nervous system
what receptors detect visible light or other waves of radiation such as infrared or ultraviolet light
electromagnetic receptors
a group of organs that work together to perform body functions
organ system
the maintenance of a constant internal state in a changing environment
homeostasis
the system that collects and excretes nitrogenous wastes and excess water from the body in the form of urine
excretory system
a cycle of events in which information from one step controls or affects a previous step.
feedback
a plant organ that is the main site of photosynthesis and transpiration
Leaf
a specialized structure that contains the ends of sensory neurons and that responds to specific types of stimuli
sensory receptors
a collection of organs whose primary function is to take in oxygen and expel carbon dioxide; the organs of this system include the lungs, the throat, and the passageways that lead to the lungs
respiratory system
environmental messages that living things respond to through sensory receptors
stimulus