Answer: Manholes are usually round, primarily because roundness is the best shape to resist the compression of the earth; covers are round because they are easier to manufacture than square or rectangular shapes, they are easier to move by rolling, and they can't fall into the opening.
Explanation:
HEY THERE!!
For a given principal quantum number or n, the corresponding angular quantum number or l is equivalent to a range between 0 and (n-1) .
This means that the angular quantum number for a principal quantum number of 2 is equivalent to:
l = 0 -> (n-1) = 0 -> (2-1) = 0 -> 1
So the answer is 0, 1
HOPE IT HELPED YOU.
Heat radiates from the fire and cooks the marshmallow because heat transfer.
Answer: The ionic formula of compound is 
and the name is cobalt phosphide.
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here element Co is having an oxidation state of +3 called as 
cation and phosphprous forms 
anion with oxidation state of -3. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral
The nomenclature of ionic compounds is given by:
1. Positive is written first followed by the oxidation state of metal in roman numerals in square brackets.
2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.
Thus the name of is cobalt phosphide.
I believe the correct answer is C, but I'm 100% on this. Hope this helped though!
-TTL
