Meiosis
Meiosis is the process involved in the production of pollen or male sex cells in an angiosperm flower.
 
        
             
        
        
        
Answer:
The correct answer is C. gases.
Chemical reaction is the process by which one or more substances are converted into different substance or substances.
The substances which undergo chemical reaction are called as reactants while the substances which are produced by the reaction are called as products. During chemical reaction, chemical bonds of substrates undergo breaking and formation process to form an entire new product which may have same or different physical and chemical properties as compared to substrates.
Energy is either used or released during the chemical reaction. When the energy is used, it is termed as endothermic reaction but when the energy is produced by the reaction, it is termed as exothermic reaction. 
Lastly, gases may or may not participate in a chemical reaction.
 
        
                    
             
        
        
        
Then answer is b. Cnidaria
        
             
        
        
        
The correct sequence is; Glycolysis-pyruvate-acetyl CoA-krebs cycle-electron transport chain. 
Glycolysis is a sequence of reactions for the breakdown of glucose to two molecules of pyruvic acid under aerobic conditions, Krebs cycle is a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins into carbon dioxide and chemical energy in the energy carriers, while electron transport chain involves a series of complexes that transfer electrons from electron donors to electron acceptors via redox reactions and couples this transfer with the transfer of protons across a membrane. 
 
        
             
        
        
        
Answer:
No viruses are not considered as living organisms, until they enter the body of the host