D. Electrons orbit in a fixed shell
Answer:
D
Explanation:
I believe the answer is D.
The answer would be B. Increased fertility downstream. Hope this helps. It's been a while since iv'e done the test, but I think this is the correct answer.
Answer: The density of lead will be 
Explanation:
Density is defined as the mass contained per unit volume.

Given : Mass of lead=
Volume of lead =
Putting in the values we get:

Thus density of lead will be 