In GCSE Science one topic studied is how organisms use nerves and hormones. This is the last of five quizzes on that subject and it looks in particular at how plants use hormones for both sensitivity and control.
We all recognise the main parts of a plant but have you ever wondered how the stem of a plant knows to grow upwards and how the roots know that they should grow downwards?
One of the characteristics of life on earth is sensitivity to the surroundings. In the case of animals how they react to external stimuli is easy to see, however, it is not always so obvious for plants. Plants don't have a nervous system or muscles but they do have hormones which they use to give them sensitivity to their surroundings. The sensitivity granted by the hormones enables plants to grow towards light and makes their roots push down into the soil.