Test Group 1 Growth Conditions: Light source is only on the side of the plant
Observation: Stems and leaves are bent toward the light
Test Group 2
Growth Conditions: Light source comes from all directions
Observation: Stems and leaves are not bent
Does this make both groups experimental?

Yes

Explanation:

Experimental research includes the manipulation of control variables to measure its impact on the dependent variables.  

Both groups are experimental because they both involve the manipulation of control variables. In the given experiments control variable is the light source and the dependent variables is the bending of plant. Both group 1 and group 2, manipulate the control variables that is light source from one direction and light source from direction showing the plant behaviour towards light.

the answer is "a.) well–developed vascular system."

explanation:

the correct answer is 2 and 4