Answer: The main function of mitochondria is to produce energy for the cell. Cells use a special molecule for energy called ATP. 
Explanation: The most prominent roles of mitochondria are to produce the energy currency of the cell, ATP (i.e., phosphorylation of ADP), through respiration, and to regulate cellular metabolism. The central set of reactions involved in ATP production are collectively known as the citric acid cycle, or the Krebs cycle.
 
        
             
        
        
        
Explanation:
The DNA strand that is transcribed for a given mRNA is termed the template strand. The complementary DNA strand is called the nontemplate strandIt involves copying a gene's DNA sequence to make an RNA molecule. Transcription is performed by enzymes called RNA polymerases, which link nucleotides to form an RNA strand (using a DNA strand as a template). Transcription has three stages: initiation, elongation, and termination
 
        
             
        
        
        
True ....................................
        
             
        
        
        
Protection of sex hormones
        
             
        
        
        
Answer:
Wilhelm Johannsen.
Explanation:
Gene may be defined as the functional segment of DNA that are heritable in nature. Genes are responsible for the formation of protein product and observable characteristics of the organisms.
The Danish botanist, Wilhelm Johannsen coined the term gene. He explained the existence of the gene by the pure line experiments of the genetics. The term gene was established in opposite to the panegenes.
Thus, the correct answer is option (d).