Question

trajectory means :
a mental representation of some haunting experience
a progression or course of events, actions, or developments
a group of people having approximately the same age
a superficial aspect as opposed to a things real nature

Explanation:

The word "trajectory" in English commonly refers to a path or course that something follows, which can be in the context of events, actions, or developments. For example, we can talk about the trajectory of a career (how it progresses over time), the trajectory of a project (its course of development), etc.

• The first option about a "mental representation of some haunting experience" is not the common meaning of "trajectory". A more appropriate word for that might be "memory" or "recollection" in a more specific (haunting) sense.
• The third option "a group of people having approximately the same age" is the definition of a "cohort", not "trajectory".
• The fourth option "a superficial aspect as opposed to a thing's real nature" is more related to concepts like "appearance" versus "reality" and not the meaning of "trajectory".

Answer:

a progression or course of events, actions, or developments