Final answer:
The statement "All living organisms are composed of cells" is a scientific fact and part of the cell theory. This theory is well-established in biology, supported by a significant amount of evidence, and widely accepted as true.
Step-by-step explanation:
The statement "All living organisms are composed of cells" is best related to a scientific fact. This statement is a part of the cell theory, which is an important scientific theory in biology. The cell theory includes several key points: that all organisms are composed of cells, cells are the basic living units of organization in all organisms, and all cells come from other cells. Over time, this theory has been extensively tested and supported with a substantial body of evidence, and no evidence has been identified that disproves this theory. Therefore, it is widely accepted as true within the scientific community.
Regarding the other options provided, a hypothesis is an initial assumption or suggestion that is tested through scientific research. A theory is more comprehensive and is supported by a collection of evidence. A discovery is finding something new through research or observation. A prediction is an assertion about what will happen in the future based on current knowledge or hypotheses.