Answer:
2. carbon 
Explanation:
carbon should be the answer 
 
        
             
        
        
        
Answer:
correct option: A. tetrahedral
Explanation:
when we talk about hydrogen bonding in water due to oxygen then need to check the number of lone pair available for hydrogen bonding because hydrogen bond form between lone pair of oxygen and hydrogen of other water molecule so there are two lone pair which forms hydrogen bond and there are also two other covalent bond with hydrogen of same molecule so total number is 4 it means they will form a tetrahedral geometry
 
        
             
        
        
        
<h3>
Answer:</h3>
5.71 × 10² nm 
<h3>
Explanation:</h3>
The product of wavelength and frequency of a wave gives the speed of the wave.
Therefore;
Velocity of wave = Wavelength × Frequency 
c = f ×λ
In our case;
Frequency = 5.25 × 10^14 Hz 
Speed of light = 2.998 × 10^8m/s 
But;
λ = c ÷ f
   = 2.998 × 10^8m/s ÷  5.25 × 10^14 Hz 
   = 5.71 × 10^-7 m
But; 1 M = 10^9 nm 
Therefore; 
wavelength = 5.71 × 10^-7 × 10^9
                    = 5.71 × 10² nm 
The wavelength of light wave 5.71 × 10² nm