What is phototaxis?

Phototaxis refers to the directional movement of an organism in response to light. It is a behavior observed in various organisms, particularly in microorganisms, such as algae and certain bacteria, as well as in some animals. When organisms move towards a light source, they exhibit positive phototaxis, while movement away from light is known as negative phototaxis. This phenomenon is vital for processes such as optimizing light absorption for photosynthesis in plants and locating food or mates in other organisms.

The other options describe different biological processes. A chemical reaction in plants does not specifically involve movement in response to light, while the response to water availability pertains to how organisms react to changes in their hydration levels, not light. The process of photosynthetic synthesis relates to the conversion of light energy into chemical energy in the form of glucose, but it does not encompass the concept of movement toward light sources, which is the essence of phototaxis.