The answer for acceleration is m/s^2
Out of the three you gave ecosystem is what I would call the most broad. An ecosystem includes living AND non-living things in an area
Community is all the LIVING things in an area (plants are included and I think bacteria is too, but I'm not sure)
Population is pretty narrow it just looks at specific species in one area. Population of mosquitoes doesn't include butterflies, if only looks at mosquitoes
Hope this helped!
Answer: the correct option is A (C.N. = 6; O.N. = +4.)
Explanation:In the coordination
compound[Cr(NH3)(en)2Cl]Br2,
the coordination number (C.N.) and oxidation number (O.N.) of the
metal atom are 6 and +4 respectively.