Red blood cells. Need glucose oxygen to convert to carbon dioxide
If you mean temperature wise then it’s due to the clouds absorbing most of the sunlight, less clouds let’s more light through
Answer : The time taken by the reaction is, 
Explanation :
The expression used for second order kinetics is:
![kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}](https://tex.z-dn.net/?f=kt%3D%5Cfrac%7B1%7D%7B%5BA_t%5D%7D-%5Cfrac%7B1%7D%7B%5BA_o%5D%7D)
where,
k = rate constant = 
t = time = ?
= final concentration = 1.25 M
= initial concentration = 2.25 M
Now put all the given values in the above expression, we get:


Therefore, the time taken by the reaction is, 
I think it’s A because each unit is worth 3