It is d, a substance that participates in a chemical reaction. You can also tell it just by looking at the stem of the term :)
The cell grows to its mature size
Well sickle cell disease requires two homozygous recessive alleles so you would have the disease but if your'e heterozygous you have the sickle cell trait.
The acidity of the body's fluid is determined by the concentration of hydrogen ions.
Hydrogen ions with the formula H3O+(H2O)n are developed by the addition of protons to one or more water molecules. It is made up of a proton or a particle carrying a unit positive electric charge.
