Over millions of years, layer after layer of sediment and other plants and bacteria were formed. ... Even higher heat or biomass made predominantly of plant material produced natural gas.
Answer:
I think the answer is C.
Explanation:
A primary source is a first hand account of an event while a secondary source is a retelling or second hand account meaning as many details will be prevalent.
Magnetic fields are an area around a magnetic material or a moving electric charge with which the force of magnet
Answer:
The magnetic flux density is 
Explanation:
Given that,
Distance = 0.36 m
Current = 3.8 A
We need to calculate the magnetic flux density
Using formula of magnetic field

Where,
r = radius
I = current
Put the value into the formula


Hence, The magnetic flux density is 