Question

what does a valid experiment require? only quantitative data only a hypothesis only qualitative data both an experimenta a control group

Explanation:

A valid experiment needs to compare groups to assess the effect of a variable. An experimental group (where the variable is manipulated) and a control group (where it's not, for comparison) are essential. Options like only quantitative/qualitative data or only a hypothesis are insufficient—experiments require structured comparison via these groups.

Answer:

D. Both an experimental group and a control group (assuming the fourth option is "Both an experimental group and a control group" as the text is cut off but contextually this is the correct requirement for a valid experiment)