1.1. In a school experiment, germinating seeds were pinned to a cork plate (which was not rotating) and left in the dark for 48 hours.

The result of the experiment is shown in Image 4.1.

Image 4.1

State the name of the:

(i) growth response shown by the germinating roots in Image 4.1;

[1]

(ii) hormone which controls growth responses in plants.

[1]

1.2. A second experiment was set up where germinating seeds were pinned to a cork plate which rotated three times per hour. The apparatus was left in the dark for 48 hours.

The result of the experiment is shown in Image 4.2.

Image 4.2

Explain the growth of the roots in the result shown in Image 4.2.

1.3. Suggest why the apparatus was kept in the dark for 48 hours.