They are both plants, also reproduction, and pollen, i think
1 air
2 water
3 food
4 temperature
5 sunlight
6 shelter
This is an experiment where the researcher manipulates one variable, and control/randomizes the rest of the variables. It has a control group, the subjects have been randomly assigned between the groups, and the researcher only tests one effect at a time.
Your answer would be Glusose
