A solution must have both a solute and a solvent, and they must exist in solution together. the solute must be dissolved in the solvent; salt does not dissolve in a sugar bowl, nor does oil dissolve in water; it is a non polar molecule. we know that sugar (the solute) when added to water(solvent) will dissolve, creating a solution.
therefore, B
Answer:

Explanation:
Hello there!
In this case, since these problems about gas mixtures are based off Dalton's law in terms of mole fraction, partial pressure and total pressure, we can write the following for hydrogen, we are given its partial pressure:

And can be solved for the total pressure as follows:

However, we first calculate the mole fraction of hydrogen by subtracting that of nitrogen to 1 due to:

Then, we can plug in to obtain the total pressure:

Regards!
At STP one mol weighs 22.4L
Moles of O_2
1 mol.O_2 can create 2mol water
moles of water
Volume of water
Normally, cortisol is present in the body at higher levels in the morning, and at it is lowest at night. Although stress isn’t the only reason that cortisol is secreted into the bloodstream, it has been termed “the stress hormone” because it’s also secreted in higher levels during the body’s stress response and is responsible for several stress-related changes in the body.