Answer:
(a) Allow movement in only one plane/direction (that is extension or flexion)
(b) The skeletal system also produces blood cells in their bone marrow
 
        
                    
             
        
        
        
Answer:
FRYVNGPVLIRKLYSWWNLIMILLQYFAIMGNLVMNLVMNTGDVNELTANTITT
The bold region of the above sequence will be in the transmembrane region.
4.b) To predict the helix we need to know the propensity of each amino acid in the amino acid sequence to form an alpha helix of the protein. Not only the propensity of a single amino acid will dictate that but also other amino acids in its vicinity will have an effect on it. More importantly, that should follow the Ramachandran plot.
4.c) I chosen that region based on the hydropathy index of the stretch of amino acids. The region of amino acids should have hydrophobic side chain because they will interact with the hydrophobic tail of the lipids in the cell membrane. So this region has higher hydropathy index than others. This lead me to choose that region.
 
        
             
        
        
        
Scientists use fossils to learn about organisms' lives and evolutionary relationships, to understand geological change, and even to locate fossil fuel reserves.
        
             
        
        
        
The solution in the berzelius glass has a concentration of 50%, the other solution has a concentration of 30%. In osmosis water moves from the solution with a lower concentration to the solution with the higher concentration. Therefore, water will move from the 5%glucose,25%starch solution to the 20%glucose, 20%K⁺,10% iodine. 
 
        
                    
             
        
        
        
Carbon is released into the atmosphere only during the burning of fossil fuels
Explanation:
During the process of fuel burning, carbon is released in the atmosphere. The human invented power plants, factories, cars and other vehicles releases carbon in the form of carbon di-oxide in atmosphere.  
However, the cellular respiration is similar to that of fuel burning as it is too a combustion process. But the carbon produced in this process fuels the inner cellular activities rather than releasing it in the atmosphere.