Answer: Genetic variation describes naturally occurring genetic differences among individuals of the same species. Gene duplication, mutation, or other processes can produce new genes and alleles and increase genetic variation. New genetic variation can be created within generations in a population, so a population with rapid reproduction rates will probably have high genetic variation. And there are the reasons.
 
        
             
        
        
        
Environmental science is the science including ecology, biology, physics etc. <span />
        
             
        
        
        
Answer:
Scientists once thought the most fundamental building block of matter was a particle called the atom. Now we know that the atom is made of many smaller pieces, known as subatomic particles. Every atom contains a central core called the nucleus, made of particles called protons and neutrons.
 
        
             
        
        
        
What looks like fluffy ball?
WHAT DOES?
        
             
        
        
        
Answer:
Option A
Explanation:
Options - 
A-avoid water pollution.
B-build thermal power plants.
C-add water features to gardens.
D-avoid drip irrigation systems
Solution - 
The largest source of freshwater on planet earth is underground water. The water beneath the surface of earth is very limited. The total fresh water reserve on earth is 3% of the total water on earth. Pollution due to discharge of waste water into the rivers and oceans has caused the degradation of not only surface water but also ground water.  
Thus, option A is correct
Drip irrigation is a means to prevent wastage of water during irrigation. Thus, avoiding it will cause further loss of fresh water.  
Addition of water feature will increase usage of water, thus it is also incorrect
Building thermal plant will also cause water pollution and wastage. Hence, option  B is also incorrect