Answer: prokaryotic cells
      Explanation:
A prokaryotic cell is a cell without a nucleus.  Since this is a simple definition I cannot explain much further, but an example of a prokaryotic cell is bacteria. 
 
        
             
        
        
        
Answer: Bundles of axons in the central nervous system are called a "tract" 
Explanation:
Axons(nerve fiber) consist of long slender projection of neurons or nerve cells that conduct and transmit impulses away from the neuron or nerve cell body. Axons are surrounded by endoneurium layer which contain protein fluid that surround each axon. 
Bundles of axon in the CNS is known as tract. We have ascending tracts and descending tracts. The ascending tracts function are to conduct and carry impulses along the spinal cord to the brain while the descending tracts transmit and carry the impulses from the brain to lower regions (downward) of the body. Tracts are identified by their origin (where the bundle start) and also the end/termination of axon bundle. 
The largest tracts are fasciculi gracilis and cuneatus which are known as ascending tracts. 
 
        
             
        
        
        
THE ACTIN has the active site to which the heads of the thick filament will bind.
The muscle is made up of two major protein fibers, which are the actin and the myosin. Muscle contractions occur when myosin and actin slide over each other in a series of repetitive events. The protein actin has a thin structure and is abundant in eukaryotic cells while myosin is a thick filament.
        
             
        
        
        
the correct answer is carbohydrates because this fat can produce both short and fast energy.  
 
        
             
        
        
        
In mitosis, the first stage is prophase. The
nucleolus disappears and the two centrosomes begin to form the mitotic spindle.
The spindle xtends between two opposite poles f the cell. Next is the
metaphase. The centromeres of the chromatid pairs align at the center of the
miotic spindle. Then anaphase, the centromeres will split that separates the
chromatid pair. They are now called chromosomes. The last phase is the
telophase. The chromosomes will then form a thread-like chromatin and for ache
envelope, a nucleoli appears. <span>The type of
cell division that produces gametes with half the normal chromosome number is
the meiosis. Meiosis is the type of cell division used in sexual reproduction.
It will occur in the testes and ovaries.</span>