C. Useful energy out of a system is always less than the energy input of that system.
Explanation:
The correct statement of the given options is that useful energy out of a system is always less than the energy input of that system. 
This is in compliance with the third law of thermodynamics which states that "energy transformation in a system is not 100% efficient". 
- At every stage energy is usually lost when it is transformed from one form to another. 
- There is no machine that is 100% efficient. 
- A machine that is 100% efficient will convert all the useful energy in it to do work and even more. 
- In system energy is usually lost as a result of heat and to overcome friction. 
- This reduces the amount of energy out of a system. 
learn more: 
Third law of thermodynamics brainly.com/question/3564634
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Answer:
BRYAN!!! stop cheating this is your teacher if you are caught again you will be getting a message home and a suspension
Explanation:
 
        
             
        
        
        
An icon is a symbolic representation of an action to be taken, given in emails or message bars. Icons are metaphorical representations of emotions and feelings which a human is unable to explain in words.
The icon used to represent an attachment is paper clip.
When we click this paper clip icon, it allows us to attach any file including a document or a picture in that particular email. An attachment may also contain a virus, Trojans, worms and other form of malware.
  
 
        
                    
             
        
        
        
Answer: Respiratory system, Excretory system, and Endocrine system.
Explanation:
Homeostasis is the process through which several organ systems work to maintain a stable internal environment in the body. There are three organs of the body which ar eaccurately maintained by homeostasis:
Respiratory system: High carbon dioxide content in the blood triggers faster breathing. Most frequently, the lungs exhale, which quicker extracts carbon dioxide from the body.  
Endocrine system: High blood sugar content causes insulin release by an endocrine gland called pancreas. Insulin is a hormone which helps the cells absorb blood sugar.
Excretory system: A low blood level of water causes kidney accumulation of water. The kidneys contain more concentrated urine, so less water from the body is lost.  
Hence, three critical areas are respiratory system, excretory system, and endocrine system that are accurately maintained by homeostasis.
 
        
             
        
        
        
Answer:
B.) Smoking tobacco products or inhaling second-hand smoke
Explanation:
It can cause lung cancer
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