Descriptive investigations involve collecting data about a system, but not making tests or experiments.
Making tests belongs to experimental investigations.
Descriptive investigations aim to draw conclusions from observations of the fenomena, while experimental investigations design tests that let the researcher to compare results on different conditions with a control situation.
There is also the so called comparative investigations which collect data from under different conditions but do not include the control situtation.
legislative, executive, judicial, judicial, judicial, legislative
The right answer is (D) all of the above. Non-verbal communication is carried out through a wide variety of signs: sensory images (visual, auditory, olfactory ...), sounds, gestures, body movements, among others. And in this case the 3 options dads correspond to gestures of body language or kinésticos, sending messages without words (act of nonverbal communication)
The answer is A. 84% sure.