You can look at groups in the same group (the columns), since they tend to have similar properties. For example, the alkali metals in group one react aggressively with water and form white compounds. 
        
                    
             
        
        
        
Answer:
 the rock breaks down when the wind blows particles of sand against it.
Explanation:
 because the sand can easily be decomposed and temperature easily accessible to it cause line of weaknesses of the rock to break down
 
        
             
        
        
        
Transverse, (similar to a cosine graph)
        
             
        
        
        
Answer:
A.
Explanation:
I believe its A because lets say the ice is alone in a jar with nothing inside no water no other ice just be its self. You put that jar inside the freezer, for 18 hours. It's not going to be heaver nor lighter so the obvious answer would be A. because you gained nothing from that ice cube it will just have to stay the same. Sorry if I'm wrong 
 
        
                    
             
        
        
        
This is definitely an observation as it is what you can see.
An inference is one you make by drawing conclusion. This is not an inference.