It is known about a point body that in one frame of reference it is at rest, in another it moves uniformly in a straight line. Can it be argued that these frames of reference are inertial? (Hint: Consider the motion of a fly sitting on a free falling rock in the frames of reference associated with that rock and the rock that started free falling earlier).
No, you can’t, because we know nothing about the motion of the frames of reference themselves.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.