Natural selection requires variation between individuals. Mutations and reproduction increase genetic variation in a population. Natural selection occurs when environmental pressures favor certain traits that are passed on to offspring.
You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.
Answer:
Some bacteria like <em><u>rhizobium</u></em> and <u><em>blue green algae</em></u> are able to fix nitrogen gas from the atmosphere to enrich the soil with nitrogen compounds and increase its fertility. The nitrogen-fixing bacteria and blue green algae are called <u><em>biological nitrogen fixers.</em></u>
Molarity can be defined as the number of moles of solute in 1 L of solution.
M = n/V
Where M is the molarity of the solution (M or mol/L), n is the moles of the solute (mol) and V is the volume of the solution (L).
Here, solute is KF.
n = <span>0.250 mol
</span>V = 0.500 L
M = ?
By applying the formula,
M = 0.250 mol / 0.500 L
M = 0.500 mol/L
Hence, the molarity of KF solution is 0.500 mol/L.
