Answer: As the glacier receded, the sediments in the stream built up to result in the formation.
Explanation: study island
<u>Answer:</u> From the given gases, the greatest rate of effusion is of 
<u>Explanation:</u>
Rate of effusion of a gas is determined by a law known as Graham's Law.
This law states that the rate of effusion or diffusion of a gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows:

It is visible that molar mass is inversely related to rate of effusion. So, the gas having lowest molar mass will have the highest rate of effusion.
For the given gases:
Molar mass of 
Molar mass of 
Molar mass of 
Molar mass of 
Molar mass of 
The molar mass of methane gas is the lowest. Thus, it will have the greatest rate of effusion.
Hence, the greatest rate of effusion is of 
Answer:
²⁵ Mg = 10.00%
²⁶ Mg = 11.0%
Explanation:
Given that:
Magnesium ²⁴Mg has an abundance of 78.99%
Hence, (100 - 78.99)% = 21.01%
21.01% is the abundance of ²⁵ Mg and ²⁶ Mg
Suppose,
²⁵ Mg = x
²⁶ Mg = (21.01 - x)%
Then;
avg. atomic mass = 
where the avg. atomic mass = 24.3050
∴

2430.5 = 2440.46915 -0.9968 x
0.9968x = 2440.46915 - 2430.5
0.9968x = 9.96915
x = 9.96915/0.9968
x = 10.00%
∴ Recall that:
²⁵ Mg = x
²⁶ Mg = (21.01 - x)%
²⁵ Mg = 10.00%
²⁶ Mg = (21.01 - 10.00)%
²⁶ Mg = 11.0%
It is used as a before and after or step by step proces