Here's why this is the best choice:
* It emphasizes the active nature of observation: Observation isn't just about seeing something; it's about deliberately choosing to notice and focus on it.
* It covers both sensory and cognitive aspects: You can observe something using any of your senses (sight, hearing, touch, smell, taste), and you also need to process and interpret what you perceive.
* It's broad enough to encompass many different types of observation: From casual observations of everyday life to rigorous scientific observations, the core act of noticing and paying attention remains the same.
While other phrases like "gathering data" or "perceiving something" are related, they don't fully capture the essence of observation's active and intentional nature.