This question refers to cell and organism respiration. Respiration involves the uptake of oxygen which is necessary along with glucose to create the energy that drives life itself.
The correct spelling is "necessary."
Neither is correct. You say "If you feel it is necessary" or "If you feel that it is necessary."
The correct spelling of necessary is necessary. Very simple. ( Actually it's in the question.)
The suffix for "necessary" is "-ary".
more necessary, most necessary
They are not necessary!
he is not necessary
unecessary
It's only necessary because people make it necessary.
are u sure it really is necessary? i mean it could be necessary as a hoax.
Warm coats were necessary for the ski trip to Colorado.
"Necessary" is an adjective. Here are examples of its use in sentences: The company said that layoffs were necessary. This fee will cover the necessary reading materials.