Meters it the SI unit for measuring length.
The correct answer is compound
Distance is the total length covered = 2m + 3m = 5m
Displacement is his distance from original position.
Displacement = 2m + (-3)m. Representing the 3m walked back as -3.
Displacement = 2m - 3m = -1m.
So his displacement is 1m behind his original starting point.
I’m pretty sure it’s Radioactive decay
