Match the following:
1 - iv, 2 - iii, 3 - i, 4 - ii
Growth of sunflower towards a light source is termed as phototropism (growth in the direction of light).
Growth of tree roots in the direction of gravitational pull is termed as geotropism (growth towards the earth).
Growth of plant roots towards or away from moisture is hydrotropism.
Growth of plant parts in response to a chemical stimuli is called chemotropism. (For example, the growth of pollen tube towards the ovule).