Question

there are many different types of scientific investigations. which of the following forms requires the identification and control of variables?

a. model - building

b. observational field studies

c. collection of specimens

d. laboratory experiments

Explanation:

In laboratory experiments, scientists identify independent, dependent, and controlled variables to test hypotheses and establish cause - and - effect relationships. Model building may involve variables but not as central as in experiments. Observational field studies mainly observe without much variable control. Specimen collection is more about gathering samples rather than variable identification and control.

Answer:

D. laboratory experiments