I think its because so the plants can absorb more nutrients from the soil while being sturdy and wide so when the plant gets snowed on it doesn't break<span />
The examination or observation of one's own mental and emotional processes.
An eon is the most inclusive
In order to conduct a research you should have an dependent variable, independent variable and the control variable. so in order to study phototropism, then you should need sun light and the growth of the plant and you must have a control that why you need a dark room.