Mr. Sang grew a seed inside a clear, plastic bag. He taped the bag to a piece of cardboard. After the roots had grown about 2 inches, he turned the cardboard 90 degrees. Now, the stem and roots of the plant were sideways. He left the plant to grow for 2 more weeks.
When he took the plant out, it looked like this. What made the plant grow this way?
A)
Being turned made the roots keep growing sideways.
B)
Gravity made the roots grow down when the plant was turned.
Being grown in a plastic bag made the roots grow the wrong way.
D)
Light made the roots change direction when the plant was turned.