Answer:
d. Radon-222
Explanation:
²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He
Alpha particle is a helium nucleus with mass number 4 and atomic number 2. According to the law of conversation of mass, the sum of the mass number and atomic number must be equal on both side of the reaction.
Since the mass number of Ra is 226 and that of He is 4. The mass number of the unknown element must be 226 - 4 = 222.
Since the atomic number of Ra is 88 and that of He is 2. The atomic number of the unknown element must be 88 - 2 = 86.
Now looking in the periodic table Radon is the only element with atomic number 86.
I believe it’s B I apologize if it’s wrong
Hydrogen bonds<span> hold the paired nitrogenous bases together. Because </span>hydrogen bonds<span> are weak </span>bonds<span>, the two strands of </span>DNA<span> are easily separated a characteristic that is important to </span>DNA's<span> function.</span>Hydrogen bonds<span> form between adenine and thymine and between cytosine and guanine.</span>
Answer:

Explanation:
Although the context is not clear, let's look at the oxidation and reduction processes that will take place in a Fe/Sn system.
The problem states that anode is a bar of thin. Anode is where the process of oxidation takes place. According to the abbreviation 'OILRIG', oxidation is loss, reduction is gain. Since oxidation occurs at anode, this is where loss of electrons takes place. That said, tin loses electrons to become tin cation:

Similarly, iron is cathode. Cathode is where reduction takes place. Reduction is gain of electrons, this means iron cations gain electrons and produce iron metal:

The net equation is then:

However, this is not the case, as this is not a spontaneous reaction, as iron metal is more reactive than tin metal, and this is how the coating takes place. This implies that actually anode is iron and cathode is tin:
Actual anode half-equation:

Actual cathode half-equation:

Actual net reaction:
