Answer: Cytoskeleton and cytoplasm
The cytoskeleton is a network of microfilaments that provide structure and support for the cell. You can think of them as the pillars/columns that hold up a house.
The cytoplasm is the aqueous fluid that fills the inside of the cell. This fluid is very important for giving a cell is shape/support. If the cytoplasm was drained out of a cell its shape would collapse like a water balloon losing its water.
 
        
                    
             
        
        
        
Explanation:
To swim, they move their tails up and down, rather than back and forth as fishes do. This is because whales evolved from walking land mammals whose backbones did not naturally bend side to side, but up and down. ... Whales do the same thing as they swim, showing their ancient terrestrial heritage.
Cetaceans are fully aquatic marine mammals belonging to the order Artiodactyla, and branched off from other artiodactyls around 50 mya (million years ago). Cetaceans are thought to have evolved during the Eocene or earlier, sharing a closest common ancestor with hippopotamuses.
 
        
             
        
        
        
The answer is a. and b. 
Diamond is pure carbon(C). Salt is pure sodium chloride (NaCl). Ocean water can contain a number of different elements mostly Water (H2O) and sodium (Na)
 
        
             
        
        
        
No the amplitude of each waves are different on different cardiac cycles. 
<u>Explanation:</u>
- The PQRST waves are used to represent the atrial and ventricular depolarization and repolarization.  These waves are reflected in ECG.  
- In this as the series, p occupies the first place then QRS complex and at last T wave. In the QRS wave complex,  R wave is said to be the largest wave.  
- The direction and amplitude of r wave depend on the electrical picture. The R wave represents the ventricles depolarization so it is the largest wave.