the answer is actually A. chemical weathering by oxidation . 
chemical weathering works on rocks that contain iron. These rocks turn to rust in a process called oxidation. Rust is a compound created by the interaction of oxygen and iron in the presence of water.
 
        
                    
             
        
        
        
A complementary process in nature either adds (options 3, 6, and 7) or removes ( options 4 and 5) carbon dioxide from the atmosphere.
<h3>Complementary processes and it's benefits</h3>
The processes that leads to the addition of carbondioxide back to the atmosphere include the following:
- The eruption of volcanoes.
- Cellular respiration carried out by organisms to release energy from food molecules.
- The use of gasoline to power cars
The processes that leads to the removal of carbondioxide from the atmosphere include:
- The production of energy-rich carbon compounds through photosynthesis.
- The dissolution of carbondioxide in rainwater.
Learn more about photosynthesis here:
brainly.com/question/19160081
 
        
             
        
        
        
Answer:
either of two masses of gray matter lying between the cerebral hemispheres on either side of the third ventricle, relaying sensory information and acting as a center for pain perception.
Explanation:
 
        
                    
             
        
        
        
Answer:
Osmosis occurs where the movement of water move from a region of high water potential to a region of low water potential. 
The water potential in blood capillaries need to be higher than the water content in intestinal so that the water will move from blood to intestine which cause diarrhea.
 
        
             
        
        
        
Answer:
oxygen, sulfur, selenium, tellurium, polonium, and ununhexium (O, S, Se, Te, Po, and Uuh, respectively)
Explanation:
i hope it helps all this are 6 valence from electron and form 2-iron.