Answer:
D or A
<em>But I do know...</em>
It's because new strains of the virus are constantly appearing and evolving, so the vaccine must change along with them.
Answer:
Explanation:
R = Rydberg constant = 
= Principal quantum number of an energy level = 2
= Principal quantum number of an energy level for the atomic electron transition = 4
Wavelength is given by the Rydberg formula
The wavelength of the light emitted is .
It forms covalent compounds
"X" in the reaction above is acetic acid with a chemical formula CH3COOH. The chemical reaction would be NaOH + CH3COOH = NaCH3COO + H2O. This is a neutralization reaction in which it produces a salt and water. The salt produced is called sodium acetate.
