Answer:
The tail of an ATP molecule is made up by 3 phosphate groups link together by the help of 2 high energy phospho anhydride bonds.
Explanation:
ATP or adenosine tri phosphate is an energy rich compound that contain adenine base, ribose sugar and 3 phosphate groups.
                   These 3 phosphate groups makes up the tail of ATP molecule.The 3 phosphate groups are designated as alpha phosphate,beta phosphate and gamma phosphate starting from the C5 atom of ribose sugar.
           When ATP undergo hydrolysis the terminal phosphate group or the gamma phosphate group is cleaved from the ATP molecule resulting in the formation of ADP and inorganic phosphate along with the generation of high amount of free energy that is utilized by the cell to perform various cellular and physiological activities.
 
        
             
        
        
        
A. endoskeleton
Endoskeleton is not a characteristic of Arthropods that has attributed to their diversity and success. Endoskeleton is defined as inner characteristics of the skeletal feature of an organisms such as bears, humans, fish and etc.
Exoskeleton on the other hand is the trait by which arthropods posses. It is skeletal feature that is described outside or is extrinsic, this is evident as crabs have their skeletons outside of their body. 
        
             
        
        
        
Cell- <span>the smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane. Microscopic organisms typically consist of a single cell, which is either eukaryotic or prokaryotic.</span>
        
                    
             
        
        
        
Answer:
True
Explanation:
Meiosis is a type of cell division that occurs in gametic cells. In this cell division, one cell is divided into four cells and the chromosome number is reduced to half therefore it is also called reduction division.
During meiosis crossing over occurs between homologous chromosomes that allow the exchange of genetic material between them that results in the formation of genetically unique daughter cells.  
In spermatogenesis during the first meiosis division, the homologous chromosomes get separated into two daughter cells reducing the chromosome number by half and during second meiotic division sister chromatids separate into two more cells. Therefore four genetically different cells are generated.