The correct option is D.
Wind has some advantages which makes it suitable as a source of energy but it also possesses some disadvantages which reduces its potentials as a viable source of energy. For instance, large expanse of land will be needed to construct wind farms and this may not be feasible especially in populated areas. Another disadvantage is that electricity production will be depended on the availability of wind, when there is no wind, there will be no electricity.
I think the independent variable is the temperature, while the dependent variable is the size of the balloon. The factor that is held constant is the amount of air in the balloon. An identical balloon kept at the original temperature. Independent variable in an experiment is the variable that the experiment plans to change while the dependent variable is the variable whose value depends on the independent variable.
The Griffith's experiment, the Avery-MacLeod-McCarty experiment, and the Hershey–Chase experiments were the set of experiments that established DNA as the key hereditary molecule. The Avery-MacLeod-McCarty experiment was an extension to the Griffith's experiment. The heat killed virulent S strain cells of the Griffith's experiment were lysed to form a supernatant containing a mix of RNA, DNA, proteins and lipids from the cell. The supernatent was equally divided into 3 parts after the removal of the lipids. The 3 parts were respectively treated with an RNAase to degrade the RNA, DNAase to degrade the DNA and proteinase to degrade the proteins. The treated supernatant was then added into the culture containing the non-virulent R cells. In case of the supernatant treated with the DNAse, no transformation of R cells into S cells occurred. The transformation of R cells to S cells occurred in the proteinase and the RNAse cases. This indicated that DNA was the hereditary molecule and not protein or RNA.

Answer:
the answer is, D
Explanation:Switching off lights when not in use protects environmental quality.
Use the equation F=ma to find the Net Force
Mass: 77 kg
acceleration: 2.3 m/s/s
F=(77)(2.3)
F=177.1 N