Which part of a plant is the least complex

What feature of cell theory is best demonstrated in the image

Which of these serves as a reference for comparison during a scientific investigation? a)outcome variable (dependent variable) b) test variable (independent variable) c)control group d)hypothesis

If water is at -10 ° c and energy is added to the water until it is 50 ° c while maintaining a constant pressure of 760 mmhg, describe the phase change of the water?