The answer is c.diffusion.
Diffusion is the movement of ions, molecules or atoms form high concentration to low concentration across the membrane without the need of any energy or any membrane gates. The oxygen enters the alveoli will be dissolved in the water vapor that is present on the wall of the alveoli and will diffuse directly to the blood across the alveolar membrane.
Answer:
False.
Explanation:
Rate of reaction also depends on the number of collision that is being happening in reacting molecules. So concentration of the reactants is also important to decide the rate of reaction.
The rate of reaction is dependent on the concentration as well.
As the concentration of reactants decreases with time number of collisions also decreases .
Answer:
2.25 M is the final concentration of hydroxide ions ions in the solution after the reaction has gone to completion.
Explanation:
Moles of NaOH = 
Molarity of the nitric acid solution = 0.250 M
Volume of the nitric solution = 0.150 L
Moles of nitric acid = n



According to reaction, 1 mole of nitric acid recats with 1 mole of NaOH, then 0.0375 moles of nitric acid will react with :
of NaOH
Moles of NaOH left unreacted in the solution =
= 0.375 mol - 0.0375 mol = 0.3375 mol

1 mole of sodium hydroxide gives 1 mol of sodium ions and 1 mole of hydroxide ions.
Then 0.3375 moles of NaOH will give :
of hydroxide ion
The molarity of hydroxide ion in solution ;

2.25 M is the final concentration of hydroxide ions ions in the solution after the reaction has gone to completion.
Answer:
Obtención. El carbono se encuentra - frecuentemente muy puro - en la naturaleza, en estado elemental, en las formas alotrópicas diamante y grafito. El material natural más rico en carbono es el carbón (del cual existen algunas variedades). Grafito: Se encuentra en algunos yacimientos naturales muy puro.