The only type of investigation that involves a control group is a. collective. b. comparative. c. descriptive. d. experimental.

The correct answer is- D) Experimental.

There are primarily three types of investigations, which are descriptive, comparative, and experimental investigations.

Experimental investigation involves manipulation of a particular variable in order to determine any change in another variable.

This method is based on controlled methods ( including control group where no change is done) , so as to test a particular hypothesis and finally draw conclusions.

Thus, option D) is the right answer.

answer: point c: b. 1/2 potential, 1/2 kinetic, point a: 3/4 of its potential energy, point d or b: 3/4 potential, 1/4 kinetic

explanation: i cant explain. it's difficult to explain.

as a general rule, scissors have blades less than 6 in (15 cm) long and usually have handles with finger holes of the same size. shears have blades scissors used to cut hair or fabric must be much sharper