Yes, all plants do; it's a required part of photosynthesis.
No. They can germinate, but will soon die if there is no light.
no
Sunflowers follow the sun because they can sense the change in light.
Sunflowers will grow in part shade but it needs some sun light and water.
Light does not absorb things. Light can be absorbed by things.
Some flowers follow the sun by heliotropic action. The flowers are able to track the sun everyday as it goes from east to west.
In order to grow sunflowers in the winter they must be given a deep pot, plenty of organic material in the soil, and at least 6hrs under a full-spectrum light (a fluorescent light will do). Sunflowers are susceptible to cold. The soil temp must NOT be less than 55F. Do remember that you have to select the variety carefully, as many sunflowers are very tall and wide.
Materials that absorb light typically contain pigments or dyes that are able to absorb certain wavelengths of light. When light hits these materials, the pigments or dyes absorb the light energy, causing the material to appear darker or change color. This absorption of light energy is what allows these materials to absorb light.
Red and blue light will not absorb the same light. Red objects reflect red light and absorb other colors, while blue objects reflect blue light and absorb other colors.
Sunflowers have adapted to a wide range of soil types and their roots may be as deep 1.5 meters into the ground. Sunflowers also move their stems so that the petals are coated in as much light as possible.
There is no chemical that will absorb light and ONLY discharge it in the absense of light, however there are chemicals that will absorb light, store it as heat, and discharge it as light slowly, so that if light is removed it will continue to glow.
An object that is black or very dark in color will typically absorb the most light because dark colors absorb light rather than reflecting it. Additionally, objects with rough surfaces or materials that specifically absorb light rays across a broad spectrum will also absorb more light.