D.  A variable or alteration to one part that affects an entire system
Explanation:
When talking about natural and physical systems, change is a variable or alteration to one part that affects an entire system. 
Systems are groups of processes that have the same overall function. There are several types of interacting components that makes up both physical and natural systems in our world.
- The part of  system is related and interconnected via the changes they undergo. 
- Changes typically causes variation or alteration of parts of a system. 
learn more: 
Biogeochemical cycle brainly.com/question/3509510
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The correct answer is option A, that is, a landfill in the region of nonporous bedrock.  
A permanent waste disposal facility where the wastes are put into the ground and covered with a layer of plastic, soil, or both is known a landfill. A secure chemical landfill refers to a landfill developed in the region of nonporous bedrock.
A secure chemical landfill is a prudently engineered depression in the ground or constructed on the top of the ground, signifying a football stadium into which wastes are dumped. The objective is to inhibit any water-related or hydraulic association between the surrounding environment and the wastes, mainly groundwater.  
 
        
             
        
        
        
Yes, protists have cell walls.
Protists cell walls are made of composed cellulose, protein strips , and silica
For some protists, we can even found components like pectin on the cell walls
hope this helps
        
                    
             
        
        
        
Answer:
convention currents in the earth's mantle
Explanation:
the convention currents move the plates and that is how plates move
 
        
                    
             
        
        
        
Thermal energy is transferred during heating.
What is thermal energy?
- Thermal energy refers to the ability to do work. As such thermal energy can also be defined as the ability of something to do work as a result of the movement of its particles.
- In other words, thermal energy is the energy possessed by an object or body by virtue of the movement of its constituent particles. 
- It is the total internal kinetic energy of an object due to the random motion of its atoms and molecules. 
- Thermal energy is a type of kinetic energy owing to the fact that it results from the movement of particles. Kinetic energy is the energy possessed by an object due to its motion.
- Thermal energy forms the foundation of the study of heat energy and thermodynamics. It is one of the oldest forms of energy utilized by mankind. 
- Its usage existed even before petroleum and nuclear power sources were discovered.
To learn more about thermal energy: brainly.com/question/3022807
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