Answer : Option B) Energy from the environment fuels production.
Explanation : Environmental fuels can be produced from lands and contribute towards production. The land can contribute for the production of a Biogas plant and help in generating energy from the plant. It uses mainly decaying matter and household wastes which are decomposed and then produce methane gas is then connected to the household kitchens.
Answer : The magnetic moment of a single nickel atom is 
Explanation :
Formula used :

where,
= saturation magnetization = 
N = Avogadro's number = 
V = volume of nickel atom
= magnetic moment
First we have to calculate the volume of nickel atom.




Now we have to calculate the magnetic moment of a single nickel atom.



Therefore, the magnetic moment of a single nickel atom is 
Answer:
I think it would be d.
Explanation:
Because it would just keep going until a force acts on it.
Answer:
All three are present
Explanation:
Addition of 6 M HCl would form precipitates of all the three cations, since the chlorides of these cations are insoluble:
.
- Firstly, the solid produced is partially soluble in hot water. Remember that out of all the three solids, lead(II) choride is the most soluble. It would easily completely dissolve in hot water. This is how we separate it from the remaining precipitate. Therefore, we know that we have lead(II) cations present, as the two remaining chlorides are insoluble even at high temperatures.
- Secondly, addition of liquid ammonia would form a precipitate with silver:
; Silver hydroxide at higher temperatures decomposes into black silver oxide:
. - Thirdly, we also know we have
in the mixture, since addition of potassium chromate produces a yellow precipitate:
. The latter precipitate is yellow.