Answer:
In biology, a gene is a basic unit of heredity and a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein. During gene expression, the DNA is first copied into RNA. 
Euchromatin is a lightly packed form of chromatin that is enriched in genes, and is often under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic. 
The genes present in heterochromatin are usually inactive. The genes present in euchromatin are either already active or will be active during growth. Heterochromatin is transcriptionally-inactive. Euchromatin is transcriptionally. (This one here is the difference) 
 
        
             
        
        
        
Well a<span> sperm fertilizes an egg to form a zygote.</span>
        
             
        
        
        
Answer:
option B is the correct answer 
Explanation:
AGAU
 
        
                    
             
        
        
        
Answer:
Mitosis is the process in which the nucleus of a eukaryotic cell divides. During this process, sister chromatids separate from each other and move to opposite poles of the cell. This happens in four phases, called prophase, metaphase, anaphase, and telophase
 
        
             
        
        
        
The correct answer is B(c?): <span>chlorofluorocarbons. Their reaction with ozone molecules is catalysed by UV radiation, oxygen (O2) is a product. Ozone is an important component of the atmosphere because it protects Earth's surface from UV. </span>