C. they are always heritable. b. they are inly heritable in gametes
        
                    
             
        
        
        
Mouth, throat, small and large intestine
        
             
        
        
        
Answer:
C) production of sperm and eggs
Explanation:
Sperms and eggs are the male and female gametes respectively. Formation of sperms and egg cells require meiotic cell division. Meiosis in sperm mother cells and egg mother cells reduces the chromosome number of half in the sperms and eggs. Meiosis also adds new gene combinations in these gametes by the process of crossing over.  
Mitosis cannot reduce the chromosome number to half in the sperms and eggs. Absence of crossing over in mitosis leads to the formation of genetically identical progeny cells from mitosis.  
Hence, mitosis can not form sperms and egg cells.  If it does, the sperms and egg cells would not have genetic variations and there would be doubling of chromosome number with each round of sexual reproduction. 
 
        
             
        
        
        
The light-dark cycle caused by the rising and setting of the sun is responsible for what are called circadian rhythms. These are biological processes that show a cycle of around 24 hours, the time between consecutive rising of the sun. Experiments have shown that without the external cue of sunlight, the circadian rhythms of organisms tend to break down. These can be reset by being re-exposed to these cues. Jet lag is due in part to a re-setting of the circadian rhythm, as you travel to a different time zone, your body has to become used to a different timing of night and day. <span>  </span>
        
             
        
        
        
angle of incoming sunlight
Explanation:
The single feature that primarily determines the variation in climate in different parts of the world is the angle of incoming sunlight. 
- Climate is simply an extended study of weather over a long period of time. 
- The elements of weather like temperature, pressure, rainfall all conditions climate. 
- The angle of incoming sunlight is by far the most important factor that determines climatic patterns on the earth. 
- Around the equator, the sun is overhead and these regions are usually hot driving a wide range of weather phenomenon. 
- The polar and temperate regions receive diffused sunlight because the sun is at an angle there. 
learn more: 
Sunlight brainly.com/question/1739812
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