The duodenum.
The duodenum is the shortest segment of the small intestine. It receives chyme (partially digested food)
from the stomach.
        
             
        
        
        
Abiotic Factor-a nonliving condition or thing, as climate or habitat that influences an
 ecosystem and the organisms in <span>it
True</span>
        
             
        
        
        
I think Autorhythmic fibers are fibers that are self excitable or on their own for example some cardiac muscle. They  repeatedly generate action potentials that trigger heart contractions.They continue to stimulate a heart to beat even when it is removed from the body. In comparison to contractile fibers, autorhythmic fibers are self excitable and do not require nervous system stimulation to trigger contractions. Contractile fibers have stable resting membrane potentials of -90mV, when a contractile fibers reaches threshold by action potential, the voltage gated fast sodium ions channels will open. 
        
             
        
        
        
Answer:
4. B cells become activated by interacting with helper T cells.  
1. B cells display antigens in MHC class II receptors on the cell surface.  
2. Antibodies released by plasma cells bind to the antigen so they will be destroyed by other cells of the immune system.
3.B cells rearrange their DNA to create a unique B-cell receptor.  
5. B cells undergo clonal expansion.
6. B cells digest antigens that bind to the antibodies on their surface.
Explanation:
B-cells get activated by interacting with helper T cells when they bind to the antigen to receptors i.e (MHC class II receptors on the cell surface) on the surface of the cell. Series of activities such as release by plasma cells which cause rearrangement of B cells causes the cell to divide and proliferate. The process through which daughter cells arise from a parent cell called clonal expansion. 
 
        
             
        
        
        
The right lung<span> has </span>both<span> more </span>lobes<span> and segments than the left. It is </span>divided into <span>three </span>lobes<span>, an upper, middle, and a lower, by </span>two<span> fissures, one oblique and one horizontal. The upper, horizontal fissure, separates the upper from the middle </span>lobe<span>.</span>