Respuesta :
When a horizontally positioned plant responds to gravity, then auxins in the lower sides of the stems cause cell elongation that bends the stem upright. The correct option among all the options that are given in the question is the first option. This action is mainly due to the nature of the plants to grow towards sunlight.
Lesson 19: Tropisms and Photoperiods Unit 2: From Microorganisms to Plants
1. A - Auxins in the lower sides of stems cause cell elongation that bends the stem upright
2. C - Thigmotropism
3. A - Phototropic and Gravitropic
4. C - The production of anthocyanin and the breakdown of chlorophyll
5. D - Exposing the plant to a brief period of light in the middle of the night