For an organism to function properly all the physiological factors should be favorable. These physiological factors include water level, pH, temperature etc. To perform the basic function of the life, it is important to maintain the physiological parameter in a particular range.
In case, these physiological parameters are not balanced, then the body of the organism does not perform well and causes illness.
So, the first blank can be filled with temperature and the second blank can be filled with range.
What are your options?
Anyways, I would say evolution
Every cell of the body contains the same DNA. So, the nerve cells and the blood cells have the same set of genetic instructions.
Different cells are produced by differential use of that DNA. Different sets of genes must be turned on and off in the various cell types (differently expressed genes).
Most cells in a human body contain a complete set of the genome <span>( the genetic material of an organism), which is two sets of 23 chromosomes, with exception of egg and sperm cells, which carry only half a set of chromosomes (23 instead of 46).</span>
