Answer:
oxygen
Explanation:
as it is in the air it can't be depleted or used up
most fossils are found in sedimentary rocks
Because you need to have a guess to know what to argue or explain in your experiment
Answer:
The number of free electrons per cubic meter is 
Explanation:
It is given that,
The number of free electrons per cubic meter is, 1.3
Electrical conductivity of metal, 
Density of metal, 
Atomic weight, A = 107.87 g/mol
Let n is the number of free electrons per cubic meter such that,


Where
is the density of silver atom
is the Avogadro number
A is the atomic weight of silver


or

Hence, this is the required solution.
Explanation:
The heat Q transferred to cause a temperature change depends on the magnitude of the temperature change, the mass of the system, and the substance and phase involved.