AP BIOLOGY

Detailed explanation-1: -Phototropism: Movement or growth of plants towards light is called phototropism. For example, sunflower turning towards the sun. Hydrotropism: Plant roots grow deeper into the soil in response to higher water concentration.

Detailed explanation-2: -Movement or growth of any part of the plant in response to an external stimulus is called ‘tropism’ or ‘tropic movement’.

Detailed explanation-3: -Plants also exhibit phototropism, or growing toward a light source. This response is controlled by a plant growth hormone called auxin.

Detailed explanation-4: -Phototropism is the growth of an organism which responds to a light stimulus. It refers to the movement of a plant toward a light source. There are two types of phototropism. a) Positive phototropism: The orientation of a plant or other organism in response to light, towards the source of light.