<span>There are two hormones that determine whether you fell hungry or full -- ghrelin and leptin. Ghrelin sounds like gremlin, and it's the hormone that makes your stomach churn and says, 'Hey, you gotta eat.' The second, leptin, sends message from fat that tells your brain you are full.</span>
        
             
        
        
        
Answer:
In terms of adaptation, fitness refers to the ability of an organism to survive and reproduce in a constantly changing environment.
Adaptive traits are very much important in a constantly changing environment as they increase the chances of survival of a population in the environment.
For example, Darwin's finches adapted to develop different types of beaks in order to get nutrition in different environments. Long necks of giraffes are also considered as a result of adaptation which helps them get the food located high on trees. 
 
        
             
        
        
        
1. Reduced production of waste materials
2. Increased reuse of older materials
3. Use more renewable sources of energy
4. Decrease the rate of fires through alternate means of warmth
5. Burn down less forests and find better means of farming
 
        
             
        
        
        
         The right answer here is option C. They occur in areas with ancient, mineral-poor soil. 
          An example of that is Amazonia in Brazil, it's one of the biggest forests on earth, and at the same time, we know its soil is poor, but at the same time it has some special materials that can be found there, such as niobium. This forest is, too, rainy almost all the time, and this many trees maintain the temperature of the whole earth stabilized. These kinds of forests can grow in this soil because of the burlap, that's organic materials from its own trees. It's consumed by them, and through this way, it survives and extends its size when humans don't use its resources too much.
 
        
             
        
        
        
A phase change is when matter changes into another form but keeps its properties