Answer:
Humus
Explanation:
Its Humus I believe. I remember learning something like this. 
 
        
             
        
        
        
The answer is (a).
Golf balls have a higher density than water hence sink to the bottom.
 
        
             
        
        
        
This is an example of sublimation where a substance goes directly from solid to a gas, skipping the liquid stage. 
        
             
        
        
        
Answer:
  v₀ = 292.3 m / s
Explanation:
Let's analyze the situation, on the one hand we have the shock between the bullet and the block that we can work with at the moment and another part where the assembly (bullet + block) compresses a spring, which we can work with mechanical energy, as the data they give us are Let's start with this second part.
We write the mechanical energy when the shock has passed the bodies
     Em₀ = K = ½ (m + M) v²
We write the mechanical energy when the spring is in maximum compression
      =
 =  = ½ k x²
 = ½ k x²
     Em₀ = 
     ½ (m + M) v² = ½ k x²
Let's calculate the system speed
     v = √ [k x² / (m + M)]
     v = √[154 0.83² / (0.012 +0.104)
]
     v = 30.24 m / s
This is the speed of the bullet + Block system
Now let's use the moment to solve the shock
Before the crash
     p₀ = m v₀
 After the crash
     = (m + M) v
 = (m + M) v
The system is formed by the bullet and block assembly, so the forces during the crash are internal and the moment is preserved
    p₀ =  
    m v₀ = (m + M) v
    v₀ = v (m + M) / m
let's calculate
    v₀ = 30.24 (0.012 +0.104) /0.012
    v₀ = 292.3 m / s