A living thing.
The basic unit of structure and function in an organism.
Made of a single cell.
Consisting of many cells.
A change in an organism's surroundings that causes the organism to react.
An action or change in behavior that occurs as a result of a stimulus.
The process of change that occurs during an organism's life to produce a more complex organism.
The process of becoming larger.
The mistaken idea that living things arise from nonliving sources.
An experiment in which all factors are identical except one.
An organism that makes its own food.
An organism that cannot make its own food.
The maintenance of stable internal conditions.
The process of grouping things based on their similarities.
The scientific study of how living things are classified.
The system for naming organisms in which each organism is given a unique, two-part scientific name indicating its genus and species.
A classification grouping that consists of a number of similar, closely related species.
A group of similar organisms that can mate with each other and produce offspring that can also mate and reproduce.
The process by which species gradually change over time.
An organism whose cells lack a nucleus and some other cell structures.
The dense area in a eukaryotic cell that contains nucleic acids, the chemical instructions that direct the cell's activities.
An organism whose cells contain nuclei.