Researchers Who Were Studying Plant Growth Raised Plants in Two

question 45

Multiple Choice

Researchers who were studying plant growth raised plants in two separate rooms. One room had taped conversations playing 24 hours a day; the other room was silent. The researchers found that the plants grew better in the room that had the conversations playing. In this study, the type of room (conversation or silence) would be ​

• A)the dependent variable.
• B)an extraneous variable.
• C)a placebo.
• D)the independent variable.