Answer:
1 living organisms are composed of one or more cells.
2 The cell is the basic unit of structure and organization in organisms.
3 Cells arise from pre-existing cells.
D-a trait that helps an organism survive in its environment
Answer:
controlled experiments
Explanation:
Experiments in which all variables are identical except for one are called controlled experiments. This where an observer tests his hypothesis by looking on changes that were brought about by one variable. The results are always dependent on one adjusted variable.