Answer:
E2F transcription factors  
Explanation:
The E2F transcription factors (TFs) encode intracellular factors associated with the control of the cell cycle. E2F are TFs that bind to promoter consensus sequences in order to activate transcription. These TFs control the expression of target genes involved in cell proliferation including, among others, genes for DNA replication and mitotic activation. Moreover, the E2F proteins also may act as a link between cell fate and the cell cycle. The retinoblastoma (Rb) is a protein that modulates the activity of the E2F family of TFs, and it has been shown that the Rb/E2F pathway is a key molecular mechanism associated with cell proliferation.
 
        
             
        
        
        
Answer: (B) Prothallus
Explanation: Prothallus is the gametophyte stage in the life of <u>a fern or other pteridophyte</u>. 
 
        
             
        
        
        
Answer-
All the bonds are hydrogen bonds  and this bond is strong
 
        
             
        
        
        
Answer:
The correct answer is b. Neutrophils
Explanation:
Neutrophils are the cells that first reach to the infection side and kills the bacteria. Neutrophils comprises most part of WBCs approximately 50-70% of total WBCs. Neutrophils kills the foreign bacteria by engulfing them and this process is called phagocytosis. 
The engulfed bacteria is called phagosome and phagosome then fuse with lysosome making phagolysosome. Now fused lysosome secrete lytic enzymes like proteases, lipases and glycosidases which kills the engulfed bacteria by digesting them. 
So neutrophils will be the first cells migrates to prevent bacterial infection in the hand of 20 year old boy who shoots his hand with nail gun.