Describe an event resulting in a secondary succession in a temperate ecosystem

Here is a quote from an npr news article: “on average, working-age adults were eating about 78 fewer calories per day in 2010, compared with five years earlier. the new report is based on data from the national health and nutrition examination survey, which collects details on eating habits and other health-related information from a nationally representative sample of about 10,000 people in the u. s.” which of the following is true about the numerical value 78? a. it is an anecdote. b. it is a parameter. c. it is a simulation. d. it is a statistic.

*i will mark you brainliest plus 10 free points * which of the following is not a basic defensive driving skill? a. a solid grasp on the instruments and controls at your disposal. b. the pre-drive procedures and adjustments to your ride. c. scanning for hazards and adequate space management. d. the post-drive procedures and adjustments during your ride. e. all of the above

Why is it essential to operationally define the variables in a study?