After few days of sowing of maize seeds in the soil, irrespective of t

After few days of sowing of maize seeds in the soil, irrespective of their position, the radicle always grows downwards, whereas the coleoptile always grows upwards. This phenomenon is known as :

[amp_mcq option1=”Phototropism” option2=”Hydrotropism” option3=”Chemotropism” option4=”Geotropism” correct=”option4″]