Adenine always pairs with Thymine, and Cytosine always pairs up with Guanine in DNA. When dealing with RNA, however, Uracil replaces Thymine. So in RNA, A pairs with U and C pairs with G. (just a fun fact) :)
        
             
        
        
        
The correct answer is (4) Autotrophic organism. 
Green plants make their own food by the process of photosynthesis using sunlight. Most of the autotrophs use carbon dioxide, sunlight and carbon dioxide to produce glucose that is used by the plants to obtain energy. Most of the oxygen comes from these organisms and decrease in the number of green plants can lead to several problems due to decrease in the amount of oxygen. Example: green plants, algae, and even some bacteria. This food and oxygen is produced by the action of autotrophic organisms
 
        
                    
             
        
        
        
A common human, they go from an embryo then develop into an infant then grow to a teen. once a teen they might go through changes... 
a plant is also evidence, they develope from a seed to a small bud and grow to a small plant.
        
                    
             
        
        
        
Answer:
A chemical element is a type of atom with the same number of protons in their <u>atomic</u> nuclei. 
Explanation:
For an example, the atomic number of Chlorine is 17, and there is 17 protons in Chlorine.
If you have any questions feel free to ask in the comments.
 
        
                    
             
        
        
        
Answer:
 Because water exhibits cohesive behavior.
Explanation:
Cohesive behavior can be explained as a behavior where molecules are attracted to each other.
And this means that,  water molecules are attracted to each  other because of their cohesive behavior. This makes them to be  attracted to other substances, such as the walls of the xylem of plants. 
In this case, it is believed that the water molecules behave this  way because they are polar, that is, there is an electronegativity difference between the bonded atoms. And this enables it to move from the roots to the leaves of the plants.