<span>The following statements explain how oxygen was introduced into the earliest atmosphere of the Earth and how the presence of oxygen affected life on Earth.
</span><span>
B) Oxygen is needed to carry out many life processes. The addition of oxygen to the earth's atmosphere assisted with the development of eukaryotic organisms.
</span>
D) Photosynthesis was carried out as cyanobacteria evolved. Oxygen is a product of photosynthesis.
        
                    
             
        
        
        
Answer:
M
=
2.0
 
m
o
l
 
L
−
1
Explanation:
The molarity, 
M
 of this solution can be calculated by a formula which is;
M
=
n
V
where;
M
= Molarity of solution
n
=Number of moles of solute
V
= Volume of solution in Litre
Given, 
n
=
4.0
 moles and 
V
=
2.0
 L, so we have enough information to calculate the molarity of the solution;
M
=
n
V
M
=
4.0
2.0
 
m
o
l
 
L
−
1
M
=
2.0
 
m
o
l
 
L
−
1
 or 
M
=
2.0
 
m
o
l
 
d
m
−
3
 if the questions mention volume of solution in 
d
m
3
 because 
L
=
d
m
3
 
        
             
        
        
        
Answer: B. Speed up the chemical reaction
Explanation: Enzymes help speed up chemical reactions in the human body. They bind to molecules and alter them in specific ways. They are essential for respiration, digesting food, muscle and nerve function, among thousands of other roles.
 
        
             
        
        
        
In order to create a hydroelectric power plant, you need water, hence the prefix hydro-. Most times, people use dams to block the water, which in a way stores it. When you need to produce electricity, you release some of the water which flows through a turbine making it spin, which then activates a generator to produce electricity.
        
             
        
        
        
What is Mutation
The major source of the genetic diversity among microorganisms upon which natural selection operates is Mutation.
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