Lassa fever is extremely dangerous (please note researchers have a rough time correctly determing how dangerous a virus is because many have not had a major outbreak and a vrius will react differently to everyones body.)
Answer: a. It receives a hydrogen ion.
Explanation: Base is a species which is capable of donating its negative quantity and accepting the positive one.
For example, ammonia is considered as a base because it is capable of donating its lone pairs of electrons and can accept an proton as well.
Here, out of the given options, Hydrogen 
is a proton which is acting as a positive species and hydroxide ion 
is a negative species.
Thus, option (A) is the correct answer as it will receive a hydrogen ion from another base making itself a conjugate acid.
MM Zn(NO₃)₂ = 189.36 g/mol
mass 1 mol Zn(NO₃)₂ = 189.36 g
mass hydrate = 100 / 63.67 x 189.36 = 297.409 g
mass 1 mol hydrate = 297.409 g
MM hydrate = 297.409 g/mol
MM hydrate = MM Zn(NO₃)₂ + MM xH₂O
297.409 = 189.36 + x(18)
x = 6
2 and a half
250 x 2 =500
250/2=125
and 125 is a half of 250
so your answer is
2 and a half
We need an equation that would relate the concentration of the original solution to that of the desired solution. To solve this we use the equation expressed as follows,
M1V1 = M2V2
where M1 is the concentration
of the stock solution, V1 is the volume of the stock solution, M2 is the
concentration of the new solution and V2 is its volume.
M1V1 = M2V2
0.266 M x V1 = 0.075 M x 150 mL
V1 = 42.29 mL
Therefore, we need about 42.29 mL of the 0.266 M of lithium nitrate solution to make 150.0 mL of the 0.075 M lithium nitrate solution.
