The question “what?” can be answered by A. survey B. observation C. controlled experiment D. All of the above E. None of the above

The correct answer is: D. All of the above

A survey is a method of collecting data from a large number of people by asking them questions. Observations are a method of collecting data by watching people or things in their natural environment. A controlled experiment is a method of collecting data by manipulating one variable and measuring the effect on another variable.

All of these methods can be used to answer the question “what?”. For example, a survey could be used to find out what people think about a new product. Observations could be used to find out how people use a product. A controlled experiment could be used to find out how a product affects people’s behavior.

Here is a more detailed explanation of each option:

• Survey: A survey is a method of collecting data from a large number of people by asking them questions. Surveys can be conducted in person, over the phone, or online. The questions on a survey are usually designed to measure people’s opinions, attitudes, or behaviors. Surveys can be used to answer a variety of questions, such as what people think about a new product, how often they use a product, or how a product affects their behavior.
• Observation: Observations are a method of collecting data by watching people or things in their natural environment. Observations can be conducted in person or by using video or audio recording. The goal of an observation is to describe what people or things do without interfering with their behavior. Observations can be used to answer a variety of questions, such as how people use a product, how people interact with each other, or how a product affects people’s environment.
• Controlled experiment: A controlled experiment is a method of collecting data by manipulating one variable and measuring the effect on another variable. The variable that is manipulated is called the independent variable. The variable that is measured is called the dependent variable. The goal of a controlled experiment is to determine whether the independent variable causes the dependent variable to change. Controlled experiments can be used to answer a variety of questions, such as whether a new product is effective, whether a new policy is effective, or whether a new treatment is effective.