Answer:
Explanation:
1. Virus's are hard to detect because of their simple construction.
2. Some mutate very easily.
3. It is hard to isolate the virus and kill it without doing damage to the host.
Answer:
The resistivity of aluminum is 2.8 × 10–8m. What is the conductivity of aluminum? (2 points) Resistivity = 1 / conductivityx = 1/ 2.8 x 10^-8Resistivity= 36714285.71 Ohms 2.
When a radioactive isotope releases an alpha particle, the atomic number of the atom is decreased by four.
So, the correct answer is B.
Hope this helps,
Davinia.
<u>Answer:</u> The original element is 
<u>Explanation:</u>
Alpha decay is defined as the process in which alpha particle is emitted. In this process, a heavier nuclei decays into a lighter nuclei. The alpha particle released carries a charge of +2 units.
The released alpha particle is also known as helium nucleus.

For the given alpha decay process of an isotope:

<u>To calculate A:</u>
Total mass on reactant side = total mass on product side
A = 208 + 4
A = 212
<u>To calculate Z:</u>
Total atomic number on reactant side = total atomic number on product side
Z = 82 + 2
Z = 84
The isotopic symbol of unknown element is 
Hence, the original element is 