Answer:
1. the process of plants taking in sunlight and creating oxygen 
2. outputs are oxygen
3. inputs are sunlight
Explanation:
 
        
                    
             
        
        
        
Answer:
Explanation:
 pH = − log [H+] , we can solve for [H+] as,
− pH = log [H+] ,
[H+] = 10^−pH,
so PH =2.4 in you case is 
[H+] = 10^-2.4 =0.00398 
The option are not correct it looks
 
        
             
        
        
        
The finagling in the hole
        
             
        
        
        
When the Pka for formic acid = 3.77
and Pka = -㏒ Ka 
   3.77 = -㏒ Ka
∴Ka = 1.7x10^-4 
when Ka = [H+][HCOO-}/[HCOOH]
when we have Ka = 1.7x10^-4 &[HCOOH] = 0.21 m
so by substitution: by using ICE table value
1.7x10^-4 = X*X / (0.21-X)
(1.7x10^-4)*(0.21-X) = X^2      by solving this equation for X
∴X = 0.0059
∴[H+] = 0.0059
∴PH= -㏒ [H+]
       = -㏒ 0.0059
       = 2.23