B. 3.77 L is the new volume occupied by the gas.
<u>Explanation:</u>
As per Avogadro's law, which states that if the pressure and temperature held constant, then an equal volume of the gases will occupy an equal number of molecules. It can be written as,

Here, V1, volume of the helium gas = 2.9 L
V2, volume of the additional helium gas in the balloon = ?
n1, moles of helium gas = 0.150 mol
n2, number of moles of additional helium gas = 0.150 + 0.0450 = 0.195 mol
We have to rearrange the equation for V2 as,
V2 = 
Now Plugin the values as,
V2 = 
= 3.77 L
So the new volume of the balloon is 3.77 L.
Answer:
The models which shows 6 electrons in the outer shell are Oxygen, Sulfur, Selenium, Tellurium and the radioactive element Polonium
Cell wall is only plant I believe
Answer:
Carbon-14
Carbon-14: with 6 protons and 8 neutrons, and an atomic mass of 14.