3: B Nervous system. 4: A Sensing and responding to its external environment.
        
             
        
        
        
An abiotic factor is a non living thing
        
                    
             
        
        
        
Explanation:
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver.
Nucleotides are composed of three subunit molecules: a nucleobase, a five-carbon sugar (ribose or deoxyribose), and a phosphate group consisting of one to three phosphates. The four nucleobases in DNA are guanine, adenine, cytosine and thymine; in RNA, uracil is used in place of thymine.
 
<em>Hope</em><em> this</em><em> helps</em><em> please</em><em> like</em><em> and</em><em> mark</em><em> as</em><em> brainliest</em><em> </em><em /><em />
 
        
                    
             
        
        
        
The answer is lower because having to return to a pre disturbance size will likely affect its genetic variation to be lower compared to the original population where in its genetic variation will be greater compared to those in pre disturbance size.
        
             
        
        
        
1. Animals 
2. Plants 
3. Virus 
4. Prokaryote