I'm not native English speaker and I'm confused about the two following options:
Should I use the possessive apostrophe or not?
Option no.1: They help in carrying oxygen to the body's cells.
Option no.2: They help In carrying oxygen to the body cells.
Best Answer
If you wish to refer to the type of cell then you must use 'body' as an adjective. For example 'cardiac cells', 'vascular cells', 'capillary cells'. There are also a few instances where the noun form is used to refer to the type of cells, e.g. 'blood cells', 'nerve cells', (here the 'blood' and 'nerve' have a adjectival force).
But I think it wouldn't be wise to use 'body cells'. In this case the 'body's cells' is appropriate, and it would be more pleasing to the ears than if you used 'the cells of the body'.