निम्नलिखित में से कौन सा तत्व आमतौर पर वास्तविक प्रायोगिक (true experimental) और अर्ध-प्रायोगिक (quasi-experimental) दोनों अनुसंधान डिजाइनों में मौजूद होता है?

In research methodology, which of the following experimental designs does not allow for the evaluation of interaction effects between independent variables?

Which of the following accurately describes why pre-experimental designs, such as the one-shot case study, are highly vulnerable to internal validity threats and are often used merely as pilot explorations?