Which of the following is not a characteristic of both surveys and observational studies?
O A. The researcher does not control or change the population.
B. Data are collected about a population.
C. Results are not used to prove cause and effect.
D. The researcher exercises direct control over at least one variable.

Amountain climber starts a climb at an elevation of 453 feet above sea level at his first rest stop he has climbed 162 feet and by his second rest stop he has climbed another 207 feet its getting late in the day so the climber starts his way down if the climber desends 285 feet how much does he need to ascend or descend to return to the original starting point